It's nothing. Step onward.
From Create Your Own Story
You step forward, but suddenly you snap something, and you hear a crumbling sound from the ceiling. Seconds later, a tree log is being hurled towards your face. Your back is suddenly shot with a beam, throwing you forward. You're slightly injured, and you swing around, still lumped on the ground. The log has stopped rolling, and you go to inspect it.
You can see the bodies of your comrades crushed by the log. This was obviously a sly trap set by the Goblins, and you feel overwhelming grief coming over you. Unfortunate that you had just killed your friends within three minutes of meeting them.
You, however, cannot let this deep sadness hold you back. You have to continue to the goblin post and slay them. The next floor of the dungeon might be nearby, and the treasure buried gets better every layer you descend.
At the end of the bridge-like corridor, with an enormous wooden door at the end of it, boasting it's large, steel rim, rusted with age. You try to open the door, but it appears to be locked from the other side.