You are right. There's a story in a recent autobiog---I've read so many I can't remember which now. It's about how Lionel Hampton, Illinois Jacquet, and Louis Armstrong's bands all tried to outdo each other in this theater. Hamp told Monk "Gates, I'll give you an extra ten if you 'jump in the river'" (jump from the balcony to the audience while playing). It's kind of hard to do this with a string bass
I think he jumped into the river from a boat they were playing on. Hampton wanted to do something spectacular because Jacquet had played Flying Home before he could.