It is possible that the whole film is a dream.
The technology used seems to be something from a different age than the present day as depicted in the 'real' world sequences.
So Leo could really be a very very old man living in our future still trapped in his first Limbo dreaming himself young and pulling on near contemporary world imagery in the same way that one might dream of being a child again but inexplicably have access to a contemporary piece of technology.
His wife may have successfully left or become lost to him in a separate Limbo and he continues to delude himself that he is responsible for her death because he planted the idea that escape is possible (but dangerous) into his own mind.