This title has a gritty story, and a strong air of reality, presenting the dour Scottish city in a light that tourists might not recognise.
But there is a small, yet niggling error, that I spotted:
Scenario: A shooting at a school. 3 deaths, including the suspect, and one injured who is rushed to the hospital. The suspect shooter, a teacher, is one of the dead.
A revolver is found next to the deceased teacher and, whilst searching, a SOCO officer finds an unspent bullet on the floor across the room.
A supposition is made: "The gun jammed " " and he cleared it" responds Rebus.
The fact is, although a shell could jam in the cylinder of a revolver, this would be quite unusual, and re-cocking or triggering the gun would move the next round under the hammer. The failed round would simply remain in the cylinder. If a shell had jammed and stopped the cylinder from turning, the only solution would be to remove the dud shell, but this could prove difficult to do, and would certainly interrupt the sequence of shooting.
This small lack of detail and poor continuity is unusual in the Rebus series, and most viewers probably wouldn't have registered it.