What do you do?

I went to pilates this evening. It is held in a room at the gym that is pretty bare which means you can hear everything. I was in class with probably 10 people. The music was up loud but you could still hear the instructor. We were in the middle of an exercise where you curl up like a ball and roll back and forth from your butt to your back. I'm in the zone, I'm doing the rolling, I'm focused. And then it happens. Pffffff. The woman next to me farts, loudly. Some how I keep my composure. I don't laugh and I keep doing the exercise. It took all of my strength to not laugh. Then we have moved on to another exercise, I forget which one. And it happens again. Pffffff. From the same damn woman. Again I keep my composure. How? I don't know. We have moved on to the stretching part of the class. I want to say this isn't true, but it happens again. Pffffff. Does this woman have no control over her bodily functions? I can't handle it any longer, I have to put my head down and focus on not laughing. I some how keep it together until the end.