"All he has to do is get a game over before he finishes changing," the shopkeeper explained. "Even though the game doesn't quite work as usual while your son is in there, there are still definite ways to lose," the shopkeeper explained.
"Like what?" Mary asked.
"Well, this is an rpg, so if he and his entire group dies in one fight..."
"Oh. So as long as he's bad at the game, there's hope?"
"Well, yeah, but he's at the very beginning, so he'd have to be really bad. It would almost be better if he was pretty good, so that he could get through enough of the game before the changes completed to get to the hard parts."
"Oh my. And is that the only way for him to escape?"
"Well, another way to get out is to slip through a few holes in the programming. Go into someplace that should exist in the world but don't, set if a chain of events that the player shouldn't have been able to do, that sort of thing. But the problem with that is while it does help your son escape, it doesn't reboot what happened like what a game over done, so any changes he already experienced..."
"....will still be there," Mary finished.
"Right. It's only happened a few times, but then again, people trapped in there have only managed to get game overs just a little more often."
Mary's eyes narrowed at the shopkeeper's word, and his nonchalant attitude through the whole thing. "And how many times has this happened before, mister?"