Avoid casting any coworkers or superiors in a negative light. Choose an example that advertises your integrity. Offering a situation where an honest mistake or human error was made, and how you went out of your way to make it right, could serve you well here.

"I had a manager whose inventory was consistently off. This person was a close friend of mine, and they repeatedly claimed they had a lot of shrinkage as a result of theft. Then I got a call from one of their employees informing me that this manager was coming in after they closed and filled up carts of goods and taking them home without paying for them, and they suspected this for years. So I had to see it with my own eyes. On the manager's day off I looked more closely at their numbers, keeping a keen eye out for this. Then I did a stakeout and documented it with my phone camera. I confronted them, and they asked me, as their friend, to let it slide. I couldn't, and they were fired. They blamed me for getting them fired, but there is no mistake that it was their own actions that were to blame."