"I'm from somewhere else, like [Alice]." (2.484)
This is when Ma reveals that she used to have a home outside of Room. The fact that a home can be a place other than Room is still incomprehensible to Jack. Heck, Jack can hardly believe that there are any other places besides Room, whether they're homes or not.
"Oh, Jack," [Ma] says, "we're never going back." The car starts moving and I'm crying so much I can't stop. (3.1001-3.1002)
It's difficult for us to tell why Jack is crying here. Is he crying because he thought Ma was dead, but she's actually been saved? Or is he crying because he's never going back to Room, the only place he knows as his home?
"[Dr. Clay] figures, soon you won't remember Room anymore." "I will too." I stare at [Ma]. "Am I meant to forget?" "I don't know." (4.852-4.854)
Ma is conflicted because she definitely wants to forget Room. It's where she was held captive for seven years. But she understands that it is actually home to Jack. It's where he was raised. What will he lose if he forgets his home?