Lift if the other lane breaks?

If your win light is on (i.e. opponent red lights, or if you get a competition bye), I usually use it as a free time run. If you want to not tip your hand to other racers, lift at either the 1000' (if running 1/4) or 330' (if running 1/8 mile) and you can use previous data to calculate what the car is running without telling the world what you are running....if that makes sense. This is more appropriate if you like to dial your car a little soft (aka, holding numbers or sand bagging).

As others said, if you take off and look back and they are broke at the line or just over the line and your win light is NOT on, be SURE and lift early enough that you don't break out or you will loose...even if your opponent is broke.

There is no rule (written or unwritten) about how to handle what you described....However, I would like to take this opportunity to say if YOU brake at any point during the run, pull the car to the side as soon as possible so that you don't mess up the grove for the other racers (please and thank you).