best thing i say is to know your bike. if its happened once, its a good chance its going to happen again. i was in a race were i had to stop on a dime and i was going pretty fast. when i locked my back wheel to skid my chain broke and i had no other way of breaking so i did the next best thing which i think is to put ypur foot on the back wheel. check your chainline to make sure its straight and get some chain tensioners if you dont already have some. another thing i learned is dont ride so aggressive when your drinking especially when riding a fixed.

ride safe ....