dude
this happened i garentee
walters son died when he was young (walter always talks about how he was super sick)and so he invented the device to travel to the other demension, to get the son from the other demension. when he traveled to the other demension he met himself. and the walter FROM THE SECOND DEMENSION, and his son, ran into the FIRST DEMENSION. thats why walter is always so confused.
shitty spelling- i know.