I do not care about ruining my karma, that would be just greedy. I need to let it play out. Karma hates greed, and if it needs greed, it will just modify itself. The vibration of karma is self regulating in its frequency of kicking ass and taking names. It gives and it takes. When you feel your instinct to do something that might be against your own interest and your own nature, but it feels right... then karma says you need to inflict suffering to yourself because its for a greater cause / purpose. The trick most of the times is to not go full retarded and 100% sacrifice yourself and become a martyr.
I'm not sure if Karma likes martyrs. Need to ask Universe more about that nonsense till I find the answer.