英语笑话:To be on the Safe Side 保证没走错

In a cinema during a performance one of the audience gets up, makes his way along the row of seats and goes out into the foyer（门厅，大厅） . A few minutes later he returns and asks the man sitting at the head of the row:Excuse me, was it your foot I stepped on when I was going out a moment ago?Yes, but it doesn't really matter. It didn't hurt at all.Oh, no, it isn't that. I only want to make sure that this is my row.