Train them for longer. Actually train them to fight. There are ways to bring someone down safely and if you know them you are less likely to hurt the person you are trying to subdue as well as yourself. Put them in a ring once they know how to fight and have them fight each other in a safe and sanctioned way. Once they graduate that level, have them spar against two partners to see what it’s like to be outnumbered. Train them to be honourable in combat ie. defensive and not out to hurt people as a priority.
And of course train them that civilians are not their enemies.
None of this requires barbaric hazing.
Oh and just as a matter of note: people don’t learn skills through chaos. You learn through repetition and once you have burned the action into your muscle memory through hours and hours and hours of practice, only then do you put your skills into chaos. Nobody gets into the ring in combat sports off the street. They practice until they can do what they need to do without thinking and only then will they be able to hopefully maintain the discipline to take the right actions under stress and chaos.