Thrusting or whatever about 2/3k I would consider fleeing. Once that happens, by the rules you have lost the fight. But if you turn back to engage, I hear that is shield running, which is an underhanded thing to do. I cannot remember if its illegal or not.
If you get cruise disrupted on the way out, and he gets close, I count is as the battle being continued, you tried to run and the attacker still wants to fight. If you defeat him YOU win. At least thats what I think.
As soon as you hit the Cruise engines, you lose. By law. But if you get CD'd, and you fight back I count it as the battle being continued or the fleeing failed.
It can be complicated on certain scenarios, I'd know.