The barrier between dimensions is shattered. I wonder how that could have happened? Who do we know in this story who blithely pokes holes in the fabric of reality for teleportation purposes, like, all the time? Want to throw out some trash? Portal. Running a bit late, even if it's not too far to just walk? Portal. Need to reach his drink, but it's all the way on the other side of a small table, just inches out of reach? Better open a gate.