You place explosives on the stairs before you and Frank run down. You find cover and the stairs explode, completely severing the path between you and the zombies. Unfortunately, it also separates you from the helicopter. Luckily, there should be an elevator somewhere. But your job is not done.
You and Frank explore the floor you are currently on. As you are looking into the rooms, you hear Josh on the radio.
"We're on the ground floor but the place is swarming with the Reanimated! Oh, shit. What is tha-..."
After that, you hear nothing but static. You hear Hank calling "Josh! Josh! Steve! Can you read me?!?"
"They're dead. They must have met Subject Zero," you say.
"Isaac, we saw Subject Zero just a few minutes ago. Whatever they encountered, it's something else."
"That must be what the nutcase was talking about," Frank says.
"What? What did you find out?" Hank asks.
"Nothing much. We found a guy that said there were worse things in here than Subject Zero."
"Where is this man? I'd like to talk to him," Hank tells you.
"I'm sorry, commander. He took his own life."
"I see. Well, carry on. Try to gather more info on this unknown enemy. We can't fight what we don't understand."
"Roger that."