As Andrew looked around, he found a translucent wall made out of plastic foil. Those walls are usually built to keep the dirt out of offices while a part of the building is being worked on.
As with most of them, this one had an entrance to slip through. Before trying it, Andrew pressed his head against it. There was no sound, and no light passed through the wall. After looking around to make sure nobody was watching him, he quickly slipped inside.
It was quite dark inside. The only light came through the thick plastic wall he just walked through. His heart beat fully of excitement, fearing he could be found. There was, however, nobody there.
As his eyes adapted he looked around. Essentially there was a hallway with a number of doors. Lots of tools were left on the floor by the builders, but it was already taking shape. Getting more confident that this place was abandoned he strolled around a bit.
Suddenly one of the doors opened.