During the 20K bike leg of a sprint tri years ago I hit a nasty pothole maybe 3 miles in- flatted right away. Still in competition mode and totally winded I tried to change out the tube as fast as I could- was carrying a pump too- really tight fitting tires and I wasn't careful enough to get the tube in right. Flatted after 20 yards. Nice 3 mile walk in a speedo back to transition at which point the race was over.....no patch kit!