sorry for the misread but i hope the instructor checked things out for you before class. as for the unknown woman you're totally right she was/is and ass..... i'm not quite sure how your foot came off the pedal. were you using clips or clipless? what kind of spin bikes? some of them are terrible trying to sort out the tension particularly when standing which requires a lot of tension. (at least i like a moderate amount of tension to stand. not too much or it is too hard on the knees) i hope your leg is coming along ok. and yeah when you slip off one needs to hit the brake right away these bikes are quite like a fixed gear. did the instructor show you where the brake was?