My friend knows that I know that she pissed herself?

lol I was walking home with her, we live a few houses away right. Well I could tell she had something wrong coz she was walking in a way that made it look like her legs were stuck together ahaha, so yeah I said bye and went to my house, I look back from the front porch and I see her running with like piss skidding out from under her school dress LOL and she whipped her head around for a sec and I think she saw me look lol!! I have school on monday,, should I talk to her or just avoid it ?