Whose blood is this?

Your face appears to be removable. Immediately in front of you is a wall of glass. It seems to be rather thick. Beyond it is darkness, though when you look closely over the edge, you notice that there is some kind of bright light far below. Behind you is a pitch-black corridor, and there are plain walls to your left and right. The ceiling is rather high - perhaps if you stacked around eleven of you, you could reach it.

[Look down the corridor].

[Approach the glass].