>>110052000see the thing is, he might go back in time and LOSE
that means he has to clean up the future the best he can
he can go back in a portal IF there's nothing else at stake, at the time, immediately. because then his conscience is clean, he didn't let anyone be hurt by inaction. if he goes back, and dies, oh well. he's not obligated to stick around and be the future's policeman forever.
It's weird to me how many people have so much trouble with this, because it's not exactly rocket science, even if it is more complicated than just 'gotta get back'