"Yes, thank you, that is the correct question," Alex says.
"In effect, I performed a summoning in reverse. Instead of pulling an object to me, I pulled myself to an object. I didn't search for a specific object, though, but for a specific universe. I had the informational energy from myself as a guide. I also sought out a practitioner. Our minds are easier to find, and since it's impossible—well, nearly impossible, I suppose—to move a practitioner through universes, I could use one as an anchor and pull myself to them." He scratches his long, scraggly beard. "I kept finding your mind, .."
No wonder your—his—your office felt haunted. Blankenship kept brushing up against your mind in his efforts to return.
"Of course, of course," Alex mutters, "how could I have been so stupid? I effectively did the same thing when I pulled myself to you. But I hadn't thought to go further and pull my entire body along. The energy expenditure must have been tremendous."
In all of your summoning practice, you've never had an experience that's at all like what Blankenship described. You knew intelligences could move between worlds, but whole practitioners? It doesn't mean that he's wrong, of course. He may have accidentally stumbled on an earth-shaking advance in summoning.
You're jealous of all of the papers he's going to get to write.
You Should Be So Lucky