If u let him go, after a few days he will spawn at the prison with an assault troop and will attack ur sectors!
Cause of him, i failed the emma Quest and as he attacks my milita squad at a sector, the game stucks for a few seconds and then, after the auto battle the results showed me, he was still alive but 1 of the milita was alive too
I couldn't continue the game, cause the fight didn't end...
So i loaded an older save file and i challanged him personal with my mercs!
Did u got the same Experience with this?