I played a round where Sam went down and everyone got the Ronin effect.
Won the map against the Mafia and got back to base. Sold up, reloaded, re-equipped and headed out to fight the Cultists.
Everyone still has Ronin. Including Sam.
you'll be pleased to know that when Sam went down again, it didn't crash or try to apply Ronin again.
You might also be interested to know that starting with the Ronin effect noticeably caused me to fail the fight (couldn't fire more than once with the rifle, effectively halving firepower). So, it's certainly effective.
I don't know if it would have lasted over to the next map, because everyone died.
I expect it would have, but that's just an assumption.
