Why?
The escalator is in a hospital and stops because the power has failed. She was going to visit her husband who is on life support, which has now but out.
Anti-humor is a type of indirect humor that involves the joke-teller delivering something which is deliberately not funny, or lacking in intrinsic meaning. The practice relies on the expectation on the part of the audience of something humorous, and when this does not happen, the irony itself is of comedic value.