Oh that type of door yes

huh?

That red part is the freakin' door .. this is a new seam street added recently.. pretty freaky .. stuff moves crazily in there as well

Same thing happened to me, with the bottom door; which led to some other place. Had to teleport back to find a key all over again. Guess I had figured it was just like the ladders which are also red, that's what tricked me... :P