You can definitely trust the cops during interrogation and convince them that what you did was reasonable and justified. Staying quiet and asking for a lawyer is an immediate red flag that will prove you are guilty since you have something to hide.

Murder and arson.

Leave no witnesses, leave no evidence intact.

Which, if you get seen while burning evidence, you’ll need to kill that witness and then burn the evidence, which may get seen, and enter a feedback loop, so that’s a huge benefit to the system

Don’t get drunk