Honestly this flashback kinda just paints Tetsuo in a bad light. He's so concerned for the poor brainwashed cult girl he goes to these lengths to rescue her... But he doesn't give a shit about any of the other brainwashed cult members? They can all go fuck themselves once he's out and allowed to marry Kasen, apparently.
He's not a hero, he wants to get his dick wet. Not a good look.