If the GM decides a compel in appropriate here then the fate point goes to the player. On the other hand if the room has that aspect or some environmental hazard that mandates athletics rolls to move with failure placing a "fall" aspect, then that is what the room is, I personally do not feel this is a compel.
In my mind a compel would be something like the player says his character runs across the zone, the GM says "I compel you to fall since the floor is covered with fish." A compel generally does not have a roll involved, either there is a skill check for weather or not you can do something, or there is a compel. There are some cases where this may not be true, but in this case I think that is correct. This also assumes that falling is a big inconvenience (ie this is a combat or chase scene, or the fact that his jacket is now covered in fish is going to hurt him later or something), otherwise it would be a weak compel.
