The wall that you've followed has opened up into a doorway. You feel your way cautiously through.

A few steps into the room and OOOF!

You land flat on your face on the floor. You grazed your head on something as you fell, likely a corner of a desk or a table. Damn it, you'd know what it was if you knew where you were!

You touch your fingers to where something warm trickles down your cheek and feel the wetness of blood.