The time passage closed first and only then he was trapped.
Gary and Yvonne were already living in the apartment he bought in the 40s for 2 seasons, which he once upon a time left in a trust so that it would be waiting dormant for him when he finally figured out that he would have in the past left it to himself...
Prereminiscent of Blink (HEY!!!! Sally Sparrow! Gary Sparrow! Psych!) Gary left the letter underneath the wallpaper in the living room in the apartment because he knew that Yvonne was in the middle of stripping the walls when he has was lost.
Just to mention that a few years earlier he met his adult son who was a vagrant until he changed the past and then his son was toffee and privileged... So the present was always in flux.