I think you'd struggle to run with a gas tank on your back.....;-)
I usually use the "I will stop if I really need to" approach to any run, and also the "I really need to stop, but I'll just jog to the next lamppost before I do" method. The plan is to trick your mind into thinking in small bits, rather than the whole thing. So, when you get to the end of the first lap, try "Ok, I'll jog 3 minutes and then turn and walk back". When the 3 minutes are up, you might feel ok enough to walk on for a couple of minutes, with the intention of then jog 3 walk 2 back. By which time of course, you are halfway round the park, so turning round would be the same as keeping going, wouldn't it?