If you take stairs and then rotate in the same square you arrive in, you will take the stairs again. Also, after you take the stairs you are reoriented to the direction of the stairs. This can be disorienting when abusing the stairs in combat. Another issue is if you hit back twice as you go down the stairs, you wind up back where you started. (a side effect of orientation change)
My proposal:
Orientation changes shouldn't activate stairs.
Orientation shouldn't change when using stairs.
