Sic Semper Tyrannis - Revenge for the South

[JMadonna]

IMO "Sic Sepmer Tyrannis" was an ad-lib line to cover Booth's exposure on stage. Think of it, people are watching a play - their belief in reality is temporarily suspended. Suddenly an actor jumps on the stage shouting something in Latin. What's your first reaction? Do you jump up and pursue him? No, you turn to the person next to you and ask 'What did he say?'

It froze the audience enough to get him out the back door.