[the ghost crosses back over to the Neverneve, Harry and Michael assume they've won, then the ghost resumes its assault on the infants]
"Christ preserve," Michael swore. "Harry, we have to step over."
[talking, debating, arguing, Harry's internal conflict of self-preservation vs chivalrous protection of the innocent]
[Harry reluctantly concedes the point, and calls his staff to himself on a stream of air:]
"All right," I said. "I'm tearing open a window that will give us five minutes. Hopefully, my godmother won't have time to find me. Anything beyond that and we're going to be dead already or back here, in any case."
[more talking, with still nothing that would resemble preparing a spell, gathering power, or anything of the sort]
[finally, something resembling relevant spellcasting:]
"Then I reached out, caught hold of reality in my fingertips, and with an effort of will and a whispered, "Aparturum," tore a hole between this world and the next.