there is an older gentleman who works with us and this is kinda what happened to him a few weeks ago.
He went into the men's room and proceeded to do what people do there when he heard someone say "Hello!"
He replied "Hello" (he thought it was odd that some guy in the next stall would be talking to him, but he didn't want to be rude)
Then he hears "How are you?"
"Fine" he says...
And then he hears "Can I call you back, the guy in the next stall keeps answering me and I can't hear you?"