Don't Stand Still (The Colour Series, #3)

Ruby Iris Williams, White's friend with benefit, staggers into his house with a critical gunshot wound to her stomach. She is barely clinging to life; fortunately, help arrives at his place in record time.

However, when the paramedics are loading her in the back of an ambulance, someone fires a shot at them, hitting one of the medics. The shooter then carnaps the ambulance with Ruby's injured body inside.

Why?

Does it have anything to do with Sullivan White's job as a Trident Officer, London M...