I remember reading that Booth jumped from the presidential box down to the stage, landing badly so that he broke an ankle, but managed to get out the back door.

As a recall, the who treated Booth's ankle, was probably unaware of his patient's identity, but was nonetheless tried and convicted as a co-conspirator in the assassination. His name was Dr. Mudd, and I recall hearing that this is the source of the phrase "his name is mud".

Sounds suspiciously like an urban legand, but it will be easy enough to LIU this evening.