My girlfriend the other day was in a park doing one of those races for life and  when I say race for life she was fleeing a rapist. That's how we met.
Are you trying to say that you met your girlfriend when she was trying to escape from a rapist?
Yes, I was just making a joke about it, but that's how we met.
I'm sure you're trying to make light of a serious situation, but you shouldn't make a joke of your girlfriend's near attack. This must have been very traumatizing for her and I don't think she would appreciate you making a joke about it. Talk to her and have her explain her feelings to you.