Your forgetting one piece of lore that does indeed let our OP be lightbound on Azeroth.
When one does the Maghar recruitment quest at the moment we rescue the orcs to bring them to our world some other races accidentally got pulled with us. If one is observant in this one time quest you can see a Saberon and Botani escape into Durotar. With this knowledge it is theoretically possible a lightbound soldier could’ve been swept up by mistake.