Oh, didn't even notice that. It's probably better that you thought that was what I meant anyway.
Shadow, she is referring to the difference between through and thorough and how the former sounds like threw. As in, I walked through my bosses door, threw my resignation letter on his desk, and gave a very thorough list of my grievances.
I was actually thinking of baseball in an attempt to not think about a 23 year-old female doing a thorough job of cleaning a particular area of her anatomy in the shower.
Edit: I spent time writing this before LD posted. His answer is more eloquent, but I'm posting this anyway.