Wait, what? I don't mean that the distance between the floor and the surface of the slime varies based on the height of the observer. That would be some pretty interesting magic, but no. I really do mean that the slime goes all the way up to the level of the floor, or almost all the way up, anyway. Let's call it exactly six inches. The iron grate, before it was lifted, was almost exactly level with the floor. The surface of the slime is six inches below that. If the slime in the pit is only knee-deep, you could easily step in and out of the pit. On the other hand, if the pit is actually a mile deep, you'd probably plunge into the slime and die or something. No one knows how deep the pit is, as there is slime in the way. So while it is technically possible to suspend Dorgath over the slime, that wouldn't be necessary to investigate the objects in the pit. Dorgath's arm is easily long enough to reach in and pull them out from a crouching position, although he'd probably still want to cover his face. This stuff smells pretty bad.