He cannot see it, but he can hear it. Slightly, only because he's pressed his ear to the door. These rooms were made to keep a certain amount of noise out after all. Once more he calls Christine's name, still trying the handle.

When he finally hears her speak up he sighs, somewhat relieved in finding her, but still worried considering the locked door and the sound of his voice. "You're going to have to move away from the door," he informs, talking loud enough so that she could hear him easily. "I'll be back in just a moment."

He had left his tools back in the other room and quickly goes to retrieve them, returning a minute later after he's gathered them all. Coming back he pulls out a chisel and hammer and starts working on the hinges of the door. It takes a bit of time - less so if he tried blasting his way in or trying to go through stone to get to the latch - but eventually the door creaks as its support gives out, letting Sam push the door until it falls into the room.