Can personal experience generate buddhistic insight outside of meditation? This is a question formed from an anecdotal experience, if this means that it is unsuitable for this format, I have no problem with it being removed.

Specifically, after seeing the news about a mass shooter, shooting out of jealousy; I felt a temporarily release from any jealousy I had myself. Can this be actual insight according to Theravada sources?
It's similar to going to a funeral, seeing the dead body and realizing that your turn is coming too. Jealousy is a subset of aversion. Aversion is 1 of the 3 evil roots that causes suffering. So if you realized that and got rid of your jealousy, that's inline with Buddhist insight.