Hi,
"I've had more heroes exit stage left than a great tragedy.
As a stage direction, 'exit stage left' is used in many plays.
However, when used in this way in conversation, 'exit stage left' simply means that someone leaves quickly without any explanation.
eg I saw Mary coming, and I really didn't want to talk to her, so I exited stage left.
It's a slightly humorous expression.
Best wishes, Clive