I had almost the same thing happen to me at the premiere for the first Harry Potter movie: the down escalator at the theatre's exit was overloaded, and started going much faster than normal.

Fortunately, as in this instance we were facing forward, it was much easier for the people to disperse, and there were no injuries.

Preventative Maintenance?

Bibliodyssey makes the mistake, but it's correct on both the comic's cover and the original flickr page title.