After taking refuge in the cathedral, Lazarus is crouched on the floor covered by a blanket. In different shots, the position of the blanket constantly changes from being over his shoulders to halfway down his body.
When The Doctor and Martha are in Martha's apartment for the second time, a boom mic is visible in front of the police box, just above the 'Public Call' wording.
At one point, the doctor shoves his "sonic screwdriver" gadget into a pipe organ, muttering "Hypersonic sound waves... inspired!" Sound waves can by definition never be hypersonic. Hypersonic means "travelling at speeds more than five times faster than the speed of sound" while sound waves always travel exactly at the speed of sound - they are the baseline.