Can you "escalate down" on an escalator?
Well, of course you can't, but of course he just did.
Much as chickens cannot cross a road without having their motives questioned, this is amusing because we can clearly see how he is back-forming escalator into escalate meaning "what one does on an escalator" when it's contrary to the word's normal meaning.
We shouldn't repeat the use, not so much because it is technically wrong, as because it was funnier the first time.