The Doctor knelt down next to several of the victims, measuring the energy levels around them with the sonic screwdriver and pinching his earlobe between two fingers as he tried to make sense of it.

"Tell the ambulances they can take their time. Fat lot of good they're gonna do." He shook his head and got up, turning around so fast his coat swirled just a little. "Alright, what do these people have in common, Billy? Come on, we can figure this out, I know it."