Root of Unity by SL Huang Page A

Any pressure on the mats would flip a relay and make the whole circuit detonate, I was sure.
    I also saw now why the third floor had gone without triggering the others: they’d armed this as a demolition trap, with the bottom two stories going off first to start the implosion and then setting off the explosives above them almost instantly, leading in a mathematically neat way to the complete implosion of the building.
    Which wasn’t even necessary. Destroying the ground floor this way would have led to the collapse of the levels above it anyway, so they could have kept only the bottom floor set and connected any breach of their security system to that—but they hadn’t.
    Someone liked overkill.
    I walked gingerly, cautious of where I put each foot, but they’d set up their charges so it was possible to live and work and walk here. The deadly security must have been prepared in advance, as this was too big a job to do in a trice after they’d sent the SUVs after me and then learned police were finding the bodies of their men, or whatever had spurred them to move base. Plastic explosives were stable enough to leave long-term—they had to have set this up from the beginning, as a contingency plan, and then wired everything live as they hightailed it. I avoided the edges of rooms and double-checked that each footfall was landing on bare wood instead of anything that could hide a pressure plate.
    I crept down to the ground floor.
    Here it was even more obvious they’d cleared out in a rush. The scattered detritus of a hurried flight was strewn across the floor—the odd knapsack or ammunition belt dropped in haste, tables knocked askew when the evacuation order had been given. Half the ground floor was a broad cement expanse they’d obviously been using as a garage; the smell of motor oil and burned rubber still pervaded the air, but all the vehicles were gone. I also found a bunch of storerooms and a room that had clearly been their armory. Much of its contents had been scooped up and taken as they ran, but there were still cases of ammunition, haphazard piles of blast shields and body armor, and large stacks of unlabeled boxes that probably contained plenty of things that would go kablooey. It might be nice to raid some of this, when I was done here.
    The charges on the first floor were more extensive than on the other two, every support pillar and structure densely layered with plastique and wiring that crept up and across the ceiling. The intended sequence of the explosion kept playing out in my mind, the mathematics extrapolating forward for me and dropping the structure neatly into rubble in the shape of its foundation.
    Overkill or not, this thing was a work of art.
    I shivered. Between the Lancer and their explosives expert, these guys had some very smart people working for them. Smart and vicious. They’d done a very thorough job of making sure their artistic collapse would happen on top of anyone who came in here.
    One long room served as a grungy computer cluster: lots and lots of machines, some dirty or old or partially in pieces. A smaller room in the back looked like it functioned as a manager’s office, with a few more computers, a wall of binders full of papers, and several large filing cabinets. A squat, heavy fire safe in the corner was bolted to the floor, its heavy door hanging open, empty.
    I sat down at the desk in the office, the one that looked like it had belonged to the big cheese, and leaned down to turn on the computer.
    It was on already. Huh. I’d expected the hard drive to be gone and for the machine to be inert. I pressed the power button on the monitor.
    Programming code appeared, white on a black screen. I scanned it—and then stood up very, very fast.
    The people here hadn’t been planning to blow this place only when someone came. They hadn’t been planning to come back if nobody found their base.
    They’d already set a self-destruct. The explosives would go in just over