“It’s terrifying, Commander,” Colburn said quietly. “We’ve been watching this for twenty minutes now, and I just feel sick. They’re moving fast and I’m not sure how much is being left behind them.”
“Me either, Sergeant,” Roslyn replied. “I had to…see. It’s too easy to just mark them as hostile on the map and carry on. Looking at them…”
“They’re…rabid, mindless,” Colburn told her. “But they’re just…people.”
“I know. All my plans are built on that, Sergeant, but I need more data.”
She heard the Marine swallow.
“We are Her Majesty’s Marines, sir,” she said quietly. “Lieutenant Evanson can get you whatever you need.”
“I don’t need Evanson right now, I don’t think,” Roslyn replied. “Your people have sensor drones, yes?”
“Of course,” he confirmed. “There’s two loaded in the default combat loadout for the exosuits. We didn’t have time to adjust from default.”
“All right. I want you to start deploying the sensor drones into the crowd,” Roslyn told him. “If the Orpheus weapon is in the air, there will be densities where the drones can detect it. In infection mode, it can’t just dissolve when hit with radio waves.
“But even so, passive scanners only. I want the drones taking air samples and examining them for nanites.” She grimaced. “I presume I don’t need to tell you to destroy those drones well away from the shuttle?”
“I’m not sure I’d bring them back aboard if you ordered it, sir, without a damn good reason,” Colburn admitted. “There might end up being accidental weapons discharges.”
Marines were…sometimes a bit too honest.
“I didn’t hear that,” Roslyn said drily. “But believe me, Sergeant, if I do order you to bring one back aboard, there’ll be a reason.”
“What are we looking for, sir?” Colburn asked.
“I need to know the infection radius, Sergeant,” she told him. “Right now, I have to assume that as soon as that mob reaches the park, everyone still above ground is effectively dead. But if it turns out that they’re only infecting people within a few meters or just those they touch…the options change.”
“I see, sir.” Colburn paused. “I’ll get my people on it. We’ll have you your data as quickly as possible.”
“Thank you, Sergeant.”
“Anything I can do to save these people, Commander. At any cost.”
Roslyn watched through the feed as the pigeon-sized drones plunged toward the mob. For a few seconds, even knowing the purpose, she thought they were going to crash into the mob, but then the engines turned on about ten meters up, sweeping across the top of the mob.
Mindless as the Orpheus infected were, they still noticed the drones. Colburn wasn’t bothering to be subtle—if nothing else, he was in an assault shuttle that was only another hundred meters up.
Several people jumped into the air, trying and failing to reach the robotic aircraft before falling. At least one of those was promptly crushed under the chaotic movement of the mob of infected, forcing Roslyn to wince and close her eyes.
“We are orbiting at ten meters,” one of the Marines reported. “Air samples are being picked up and analyzed. Passive opticals aren’t picking up anything, but we are talking nanotech…”
There was a pause.
“Air samples are clean so far as we can tell,” Colburn finally told Roslyn. “Ten meters up is probably equivalent to something like…a hundred meters horizontally for a nanite, though. We’ll dump the air and lower the drones for another pass.”
“Carry on, Sergeant,” Roslyn replied. “I’m listening, but you know what you’re doing, and I’ve got a few other irons in the fire.”
The mob Colburn was orbiting was the closest to the park by a kilometer or so and moving quickly—but it wasn’t the only chaotic mob of Orpheus infected. The only thing that had saved them so far was that the infected couldn’t use vehicles of any kind. Even fast walking for a mob was only four or five kilometers an hour.
No matter what happened, Roslyn had an hour. That would only get another twenty-five hundred to three thousand people underground, though, and she wasn’t sure how many people they could fit in the lab.
If they had ten thousand in there, they were probably already starting to fill the spaces outside the decon chambers.
“Drones are circling at five meters,” Colburn’s Marine reported. “Still nothing at this level on the exterior optics and we are taking air samples.”
Roslyn figured there had to be some level of dispersal from the infected. As Colburn had noted, though, for every meter the nanites went up, they probably spread out ten.
But if five meters up was clear, that gave her a radius she could engage the infected at. She didn’t want to kill them—but if push came to shove, the Guardia could probably hold the infected a hundred meters away.
They’d kill a lot of innocent people doing it, and Roslyn wasn’t sure she’d be able to live with herself for giving the order…but it would save the lives of everyone in the park.
“Internal air examination shows nanites at roughly two-point-one parts per billion,” Colburn said quietly. “I don’t know if that’s enough to infect—I’m going to guess not—but it does suggest a maximum limit.”
“Understood. We don’t really have another use for those drones right now, do we?” Roslyn asked.
“No, sir,” Colburn agreed. “We’re going to cycle them through at each meter as we go and see, well, how low we get.”
The answer turned out to be “one hundred and eighty-two centimeters from the top of the crowd.”
That was the height at which the Orpheus infected started to successfully yank drones out of the air and smash them on the ground.
“Okay, so they’ve wrecked fourteen drones,” Colburn concluded after taunting the crowd for a minute. “But we now have data at one-point-eight meters from the infected.”
“And?” Roslyn asked.
“At one-point-eight meters, we’re up to about a hundred parts per million, which my counter-bioweapon training suggests is infectious,” he told her. “Given
