"Psychic interference in there," he said, rubbing his temples in an effort to soothe out the pounding. "Heavy. Like something's dumping out all the bad noise it's taking in."

He kept hold of Donna's hand, but walked a little slower as he stepped through the door.

"If something goes wrong," he said. "You need to get up there, toss a fire alarm, and get back to the TARDIS."