Self-defense principle in other contexts

One of my questions for last week's Q&A was whether the self-defense principle is applicable in, and can be adjusted for, matters other than life and death. For instance, suppose you have a colleague at Workplace, Inc. who, for whatever reason, is trying to get you fired. Would it be justifiable to somehow sabotage his work to protect your own job security?

Upon reflection, I don't think this would be appropriate. That sort of ends-justify-means business paradigm seems to be the root of the unethical dealings that collapsed the economy.