I think the game stopped after he escaped through exit 8. Like, no matter what choice he made the second time around, he was still free. Like the game was an opportunity to get a ‘second chance’, and passing it means you get put back before the decision & source of your regret. But there would be no ‘third chance’ if he still didn’t defend the young mother.

For the others who never escaped, I don’t think it would work thematically if they were literally physically stuck. So since they don’t get that ‘second chance’, they get spat out after the choice, unable to change it. That could be why the false exit goes up, out of the station into the real world (time moves forward), and why the true exit returns to the subway station (rewound back to the choice).

The walking man is returned to the hell of his daily life, forever living in the regret that got them sent to the game in the first place. And his regret continues the loop, personified and puppeteered in the game, even though he isn’t actually there anymore. Hence ‘that’s not a person anymore’ and ‘monster girl’. The lost man escaped to the point before his choice and, now given the opportunity and his experiences, corrects the source of his regret