Sometimes it happens that in an instant you either relax a lot or start playing very self-confident and lose your stack. I try to follow the game and my mistakes, such mistakes are worth the tournament.
Is there a right way to play when stacked. You could become the bully, you could see lots of flops with a wider range. Or you could tighten up and preserve the stack. I really do think it depends on the table & what your ranges are.