The hospital shook, and Kira stumbled. “What was that?”

The noise continued, a distant rumble, deep in the bones of the earth.

Green raised his rifle at Armin, and one of the Ivies saw the move, perhaps even anticipated it, raising his own rifle at Green. Armin leapt through a side door and out of sight. The entire exchange was so fast Kira barely even registered it.

“Holy—” Marcus spluttered, but that was all Kira heard before Green fired a long, loud burst into the hallway, scattering the Ivies, and pulled him and Kira back into the stairwell. The Ivies took cover and returned fire, but the three companions were already diving down the first flight of stairs, throwing themselves to the floor. Bullets riddled the door above them, tearing through the wood in a furious hail of splinters and shredding the drywall on either side, only to ping and ricochet off the thick concrete steps. At the first break in the shooting Green fired back, and urged the other two farther down the stairs. The rumble they had felt hadn’t gone away; instead it was gathering in intensity.

“We can’t leave,” Kira shouted. “That’s my father!”

“Your father wants to kill you,” said Green.

“I have to talk to him,” Kira insisted, trying to get back up. “I have to stop him.”

Green threw her back down, shouting to get through to her. “We’ve lost the advantage up there—they have the numbers, they have the high ground, and they have cover. Put your head above those stairs and they will shoot it off.”

“But they have a rotor on the roof,” Kira snarled, trying to wrench free of him. “They’re not trying to occupy the floor, they’re trying to get away!”

Another storm of bullets ripped through the air, and the three crouched down, covering their heads. Marcus crawled to Kira’s side and shouted in her ear, barely audible above the gunfire.

“There’re stairs at the other end of the hall!”

Kira nodded, and they crawled down out of the line of fire. “Each floor is a long T shape,” Kira explained to Green. “We’re on one branch of the T, but there’s another staircase on the end of the other branch, where we can get up behind them.”

“You don’t think they’re watching it?”