Bug in movement system
OK, I can report, that if I go down a stair while ducking, I can't stand up until I'm on the bottom. I'm always moved down automatically. In some cases I have a chance to lower my speed by pressing the backward-movement-key.
I have tested it on the rather short stairs in Arena "U4 Processing Station" and on the long stair in the beginning of Arena "The Pit". The problem is, that your movement is uncontrolled for some seconds and you can't avoid enemy shots in this time.
If you recognize this as a bug, which is what I hope, you could fix it, or make player clipping over the stairs, which I would prefer because of the better bunny-hoppabilities.