This is one of a collection of stories that are like “Final Destination” meets “The Monkey’s Paw” (W. W. Jacobs, 1902). As such, they are tragedies more than either mysteries or horror, and would appeal most to readers who enjoy the inexorable pull of a story arc that leads to doom. In each story, a protagonist makes a wish that comes true with fatal results for someone, often the person making the wish. Nothing supernatural, but just how things work out. (Or is it?) The technical details surrounding the fatal (or near-fatal) event are drawn from real cases in the US OSHA incident report database or similar sources and are therefore entirely realistic, even if seemingly outlandish. The plots draw lightly from cultural beliefs around actions such as pointing at someone with a stick or knife, wishing in front of a mirror, or stepping on a crack.

Damien spent many of his breaks during night shifts on the hospital roof with a spotting scope and a lightweight aluminum collapsible tripod. Many of his coworkers understood that he was a keen astronomy enthusiast. In truth, Damien was less into celestial bodies and more into observing the body of Celeste, a nursing student who lived in a block of apartments opposite the hospital administration block. At night, he could view many of the apartments, balconies, and the rooftop garden from his vantage point, and he did so enthusiastically. The inhabitants, perhaps under the impression that nobody would be in the administration building at night, were less constrained than usual. Some rumors had started about Damien’s nocturnal habits, with growing suspicion that maybe the intensity of his commitment to this hobby went beyond stargazing. One thing seemed incongruous: If simple astronomy was the object of his passion, why was it that he seemed very reluctant to share it? He quickly turned down anyone who wanted to go up to the roof with him. On the few occasions when he agreed to let one of his workmates take a look, he cut it short.

Winnie R. Burns, PharmD, was a senior member of the pharmacy team and had been given the lead role in a new drug logistics project. The project was to evaluate the role of unpiloted aerial vehicles, or drones, in delivery of urgent or high-risk drugs from regional logistics hubs to medical facilities in and around the city. It was an exciting project in many ways, but as usual, expectations were far too high, capabilities far too modest, and complexities far too tangled. There was also a heated tussle over who got to set the requirements and whose budget was meant to pay for the project. On the plus side, Winnie could see clear benefits in reducing delays in supply, especially of those drugs with tight cold-chain parameters. A vaccine or biologic drug that needed to stay well below freezing right up to the point of administration could not tolerate delays due to traffic jams and the like. The ability to fly directly over the city streets and land on the hospital roof would all but eliminate delays of that nature. For scheduled drugs that might attract hijackers, drones removed humans from risk and presented fewer opportunities for theft.

One problem that she and many others had thought would be difficult turned out to be far easier: landing and launching the drones. Despite the rooftops being fairly cluttered with communications equipment, cooling towers, and a helipad, she was actually able to find several spots that adequately met the needs. On the downside, getting approval from authorities for fixed flight corridors and having charging stations on the rooftop proved to be a pain in the neck. For one thing, it was hard to get people from various authorities to accept that approval was their responsibility, and ironically, it was equally strenuous to convince some people that they in fact had no authority to deny permission to fly drugs or human tissues across the city sky. Flying live attenuated pathogen samples seemed to have everyone’s hair alight, and she was faced with vehement camps of people, with one half insisting that it was their jurisdiction for any approval to be granted and the other half arguing passionately that they had a right to stay the flights and put any such transport on hold. It literally gave Winnie nightmares in which she dreamed that shouting people with clipboards were pursuing her through grimy streets and burned-out warehouses.

Another unexpected source of opposition were the people doing environmental protection evaluation. Although they were entirely on board with the reduction of hydrocarbons, carbon, and congestion effects, they were making a big fuss over the noise pollution impact. Most of the drones were a quadcopter configuration whose high-revving motors resulted in loud and high-pitched buzzing that was thought to have biological effects on animals and humans alike. To show that this had been part of the requirements and subsequent evaluation, Winnie had to carefully write up requirements, develop metrics, and conduct suitable trials. Two candidates met the need for the low noise footprint, but did so in interestingly different ways. The one had toroidal blades that were highly tuned for specific speeds and loads and were far quieter than all the other eVTOL multirotor examples. However, they lost lifting capacity or range if the narrow speed or load ranges were not met. The other candidate was a head-scratcher. It had only one propellor and used it only at altitude when it wasn’t just gliding, but required a slingshot launch system and either a parachute or arrestor hook capture system to receive the payload.

Winnie was excited about how this second candidate was shaping up, but there was a crucial question to be answered. If the hospital invested more in the solution, the glide-drone option could provide a far quieter and more energy and carbon efficient option, with a longer range, larger cargo weight, and higher speed than the other candidates. Those advantages could only be realized, however, if the hospital didn’t have the drone just drop a payload on a parachute, but caught the whole drone. Once the cargo had been removed, a return cargo or empty bird would be recharged and catapulted from the roof. The capture and catapult process and equipment did not come cheap, either in complexity or cost.

After an extraordinary slog through meetings, she had at long last been given clearance and funding to trial the drone capture part. If that was successful, she might have a stab at building and testing a drone launch system. There were three options for a launcher; the first was a compressed air or steam launch. The second was a mechanical system that worked like a crossbow. The third system used an electromechanical linear motor approach, much like a rail gun. The compressed air was the most well-known, but was noisy. The mechanical system was less noisy and easy to maintain, but prone to failure and could be dangerous for the operator. The railgun system was quieter still, highly reliable, and most energy efficient, but required exotic materials and specialist electrical skills to install and maintain. None of them, however, were of any use unless the project proved that they could catch the 35-pound bird with a 15-pound cargo at a terminal speed of 35 MPH.

The initial concept meeting with stakeholders had not gone well. Looks of alarm spread across faces as she described how the fully laden bird would be catapulted, cruise using thermals and an onboard electric motor, and then glide to the target. “Target” was perhaps a bad term, because faces went from “concerned” to “freaking out” as she described the navigation and clever air braking system to slow it from a descent speed of nearly 150 mph to 25-35 mph when the arrestor cable caught the bird. The image many had was that any malfunction and a 50-pound missile laden with a potentially dangerous warhead might hit the hospital going up to 200 mph. It took a lot of work by Winnie and an array of external experts to walk them through the safety features and mitigations, as well as the high safety record of thousands of previous flights. At a certain point, faces relaxed, and approval was given for testing of captures, but only after hours and only with approaches in which the building was unoccupied after hours and would not endanger clinical activities.

It was a month before the arrestor cable setup had been statically tested, they had done several glide-by checks, and they were ready to catch an empty bird. They picked a Friday night for the first test, because the HR department facing the approach path of the bird would be empty, and if the bird did crash through the windows, they would have the weekend to clean up and restore. At 11 PM, the bird launch from the vendor’s base 15 miles away climbed to a nominal cruising altitude of 1,000 feet and was navigating correctly to the roof of the hospital. Winnie and her team monitored its altitude and heading on a PC in their pharmacy conference room. Each time a shift in updraft or crosswind caused the bird to deviate, they anxiously watched for it to correct itself, and heaved sighs of relief when it flawlessly did so. In a little flight elevation graph at the bottom of the screen, a vertical line changed from dull blue to bright green, announcing that the bird had reached its descent. The air speed and ground speed indicators climbed as the altimeter wound down. The bird was now using gravity to speed up, going 198 mph through the air. It was not long before another vertical color bar illuminated and an annunciator showed that the bird had deployed airbrakes as it entered the final stages of descent. The airspeed indicator wound down from over 200 to 150 … 140 … 130 mph.

The numbers steadily wound down as the altitude continued dropping, and the distance to target and expected time to capture dropped with it. In the final stage of descent, the bird would shift from nose-down to nose-up, climb slightly, and drop a hook as it presented a larger profile to the cable that had been raised by the two hydraulically operated poles across which it was stretched. Tension in the board room was at a peak as the annunciator reported that the poles were erected and the cable was ready.

Damien had been engrossed in the apartments below. He had just brought Celeste into view as she walked from the bathroom. His fingers trembled slightly, and he held his breath as he gently rotated the eye piece to get him in closer. A sudden unfamiliar hissing and humming noise startled him, and he stood up and spun round trying to make sense of the noise. But he did not have time to make sense of two dark angular objects rising up in the rooftop gloom or the loud satisfied click and hum they made as they locked themselves. Before any thoughts to explain the sounds and movement, the 35-pound missile moving at 37 mph hit him between the shoulder blades and permanently removed him from the role of active peeping-tom.