Hey, man, vengeance is a luxury we just can’t afford in this economy.
Really, seeking revenge for a fallen trainer seems foolhardy regardless of your financial situation. Think about it. Some dude just rolled up and effortlessly wasted the guy that’s been explaining to you — at considerable length — how to not get killed by people. I’d say he’s rather spectacularly proven that his advice on the subject of combat is not to be considered.
Particularly when it comes to dealing with someone like Shun, the Demonic Man-Slayer With Very, Very Large Biceps.