Lift if the other lane breaks?

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).
Depends on the situation as stated. There are no curtesy rules regarding lifting when the opponent breaks.
Thanks, that is my main concern, I don't want to accidentally commit bad sportsmanship again. I wish there was a list of some common "do's and don'ts" for track ediquite.