Uh, okay, so obviously he can't reach the button. But on a rainy day... Is he so wet he can slide up walls? o.o no uh. Oh wait, actually I know this one xD never mind.
ding ding ding!Haha figured it out cause of what Swate said about being wet. If its a rainy day, You usually bring a unbrella! Did he push the 7 floor button with the umbrella?