While reading SCP-2264 i noticed something quite interesting that "the Wandsman of Kul-Manas" said:
"There was another; a stranger in a strange land. It appeared as though they did not know where they were, smelling of fear. I cannot imagine how one might accidentally stumble upon Alagadda, I did not believe such a thing was possible. They vanished soon after yet I never witnessed them leave. Simply gone in a blink."
Is it possible this "stranger" was SCP-507? Appearing out of nowhere, seemingly not knowing where they are, being similar in aura to the other humans, being scared and vanishing suddenly sounds alot like an unwilling interdimensional traveller to me.
Maybe i'm just talking out of my ass here, i dunno it might be explained what it was somewhere else.