They'd know in a few moments.
The sapper and assistant pulled their D rings first, opening their chutes and beginning a slow, circling decent. They would have a minute to hang in the air. If things went bad on the roof, they could aim themselves away from the disaster.
Penny and the other Marines waited longer, then opened their chutes next, planning on coming in a mere fifteen seconds behind Kris and the leaders.
''They've finished their comm check,'' came from the Halsey's intel boss, now at Penny's place in the police incident command center. ''You have fifteen minutes before they call them again.''
Kris didn't answer. She was three hundred meters above the ground as she opened her chute. She had just enough time to stabilize her canopy, spot her target on the roof turning away from her, and pull up her rifle.
She aimed for the weak spot at the neck between the helmet and back, easier to hit from this angle. ''Ready,'' she said.
''One.'' ''Two.'' ''Three,'' came back to her.
''Shoot.''
Her target crumpled as she fired, riding the trigger to let more rounds go as she moved her aim up to the helmet. It shattered under her stream of darts. Maybe the armor wasn't as good as advertised.
A quick glance around showed her no one still standing on the roof. Kris let her rifle drop by its sling, got her hands back on her controls, and tried to aim her chute for a nice, soft, walkaway landing.
An updraft off the cooling building spoiled that, or maybe it was the concrete below. Part of her canopy lost lift early. She ended up standing on the edge of the roof, half her chute with her, half trying to drag her over the side. With an effort she tumbled awkwardly onto the roof's gravel floor and lay there, struggling with her lanyards until Jack trotted up.
''You want a hand?'' he said, grabbing a fistful of line.
''I don't know that I'd applaud that landing,'' Abby said, joining them and hauling the canopy up where they wanted it.
''Even out on a cold night, all a girl finds is critics,'' Kris said. She'd caught a glance of her handiwork lying in blood. It was better to laugh at this than think of that.
Out of the night, a chute came down. The Marine was out of it in a second and racing for the radar. She nodded happily and plugged a black box into it. If the codes were right, the radar would only make happy noises from now on, no matter what it saw.
Penny was also out of her chute, riffling through a downed roof lookout and muttering to her commlink. ''We got the comm codes for them. They did have rockets, but they're really stupid SAL-9s. Any kind of countermeasures should take care of them. Nothing on the explosives frequency though.''
''Appreciate what you gave us. Dump those rockets over the side, please. No use the skipper having to face them if, you know, you screw up tonight.''
''We understand,'' Kris said as Jack helped her up.
''You kind of rubbed your black paint off your ass,'' Abby told her cheerfully. ''I didn't bring along any spare paint.''
''I'll just have to keep my enemy in front of me,'' Kris said, trotting to the airshaft. The sapper cut off the lock and lifted off the cowling. Abby rummaged in his bag of tricks, pulled out her own smaller bag, slipped into a harness, and got ready to go into the shaft as they snubbed down her line to a nearby air-conditioning unit. Ready, Abby went in with professional panache, then waited for a second while the sapper put a bit of armored cloth between her line and the sharp edge of the shaft. Then she dropped. The sapper shined a laser range finder over her shoulder. He blinked it, and she stopped.
A second later, light showed from her torch. Warm air, then cooler air came up the shaft. ''We've struck air conditioning,'' the Marine combat engineer said. The torch lasted a bit longer, followed by the sound of metal bending and tape ripping. ''She sure is a professional. Asked me for tape to take care of the sharp metal ends.''
''Professional, yeah,'' Jack muttered. ''I just wonder at what?'' Kris could feel the Marines' curious stares in the dark.
She'd gotten into harness while watching this. When Abby's line went slack, Kris did a somewhat less graceful repeat of her maid's drop, carrying Abby's rifles and grenade load.
Abby's harness and line passed her on the way up as she came down. She snaked herself into the air duct, passed a rifle to Abby, and wiggled out of her harness while Jack came down. By the time Kris was ready to move forward, Abby was in a larger section of air duct, at a vent.
''Want out of here?'' she mouthed to Kris in the dim light from the grille.
Kris shook her head. There could be cameras out there. Or trip wires. Or terrorists walking around. Since they started checking out the center with the heat sensors this afternoon, no one had gone near the air-conditioning vents.
Or was that because they'd already done them?
Kris paused as that thought kicked the tire of her plan … and air leaked out. What had those two guys they'd shot this morning been up to? She signaled Jack to hold.
''Get nanos down here,'' she ordered.
A minute later, they released the nano scouts. Another minute more, and they had identified four trip wires to something.
''Abby, open the vent,'' and out they went. Penny knew where their own cameras were. They sent out their own nano scouts to search, report back, not destroy. Not so much as breathe.
Slowly, they began a zigzag course through the meeting rooms that brought them up, a hundred meters from the door that led into the exhibit hall that held the hostages a good five minutes before the next comm check with the roof.
Problem was, covering that last hundred meters.
Directly ahead of them in the central gathering area, several tables had been upended. Behind them, heat signatures showed four terrorists asleep. Two were seated in chairs at a table playing cards and glancing every once in a while at security camera feeds or at the wide corridor where Kris and her team lurked in the darker shadows.
Two hundred meters to Kris's left, above a twenty-meter wall, was the upper level. Along its rail, eight rifles showed. Maybe the terrorists behind them were awake. Maybe they slept. No telling from this angle. From the heat intel, Kris knew that there were tables on their sides up there and more shooters. That was why she was down here.
Two hundred meters to Kris's right was a drop down to the lower level. There were gunners there and a whole lot more trouble that would come running up here and hit her from behind, but all hell would have to break loose before she'd have to deal with them.
The sapper signaled the meeting room beside them was safe. Kris handed off her M-6A4 to a corporal, the next-best shooter, and took his M-6. The Sergeant signaled him and a private to hold this area, and Kris entered the meeting room, crossed it quickly, then waited while the engineer crawled across the way to check the next one. Since that put him in full view of the two card players, everyone quit breathing for a while, then quit breathing some more as they did their own trip.
But the card players played on, undisturbed.
That move, with a zig through a service area, brought Kris and her team to an almost unnoticeable workers' access door right next to the wall. A hundred yards away was another one of those small doors that the public ignores but workers put to good use.
Here was the problem she had never solved. If she ran for the door, they'd mow her crew down. If she fought her way there, they'd have time to blow the hostages a dozen times over.
Kris took a deep breath. ''Command center, Regal is at Alpha. I would appreciate that demonstration.'' Hopefully the SWAT teams in their battle suits could distract the upper and lower hall terrorists enough. Kris had learned at OCS that hope was not a plan, but hope was all she had just now.
''Slight change in plans,'' came on net in Santiago's voice. ''Zodiac landers 1 and 2 will engage the hostiles in five seconds, three, two, one.''