The Doctor beamed at Wilf. Good to know where Donna got her adventerous spirit from. It certainly wasn't her mother. The Doctor panicked internally that Sylvia might magically show up and yell at the two of them, but he decided he'd worry about that when the time came.
He followed the device's signal, gesturing for Wilf to follow. While the signal simply seemed to lead in a straight line, even two blocks down the Doctor noticed they hadn't managed to get closer to it.
"And we have odd occurrence number two." He paused. "Odd occurrence. I like that. Anyway, it looks like the signal's either changed, moved, or it's moving along with us. We're not getting closer."