Bones push the emergency door, but it doesn't budge. With a grunt of effort he applies more force and with a snap of metal and the sound of rusty hinges the door slams open.
Your flashlights sweep both up and down the stairs, but the staircase looks empty.
You turn around and inspect the door, someone has tried to weild the door shut, but did a very bad job. The bolt locking the door is opened.