Why doesn't confusion redirect stair movement?

[XuaXua]

If a player is confused and tries to move, he tends to move randomly (or semi-randomly?)

If a player is confused and standing on the stairs, my experience has been that he is always successful at climbing those stairs.

Is there a reason why confusion shouldn't redirect a stair climb attempt into sideways movement, or if standing on a stair, consider translating sideways movement into a stair climb?

[PleasingFungus]

There's a chance of stumbling on the stairs and going nowhere, iirc.

[damiac]

Yeah, I've gotten that before, you basically just waste a turn instead of going up/down. It would suck if it could make you step off the stairs, although it would be in line with its usual effects.

Having confused movement sometimes send you up/downstairs would rarely matter, but when it did happen to send you downstairs/down a hatch it would really suck.