This was a "service failure" and compensation is warranted
All elevators are supposed to be mantained in good working order and are inspected annually. You were stuck for 2 1/2 hours in the hotel's elevator, that is completely unacceptable, they should comp your hotel stay and give you free nights (in the future) to come back and have a "better experience".
Did you contact Hilton Honors and explain what happened?
RC