This is one of the qualifications available for a police CP officer .Authorised firearms officer medical enhanced trainingFirst Aid Training Courses Essex, London & Herts | In house
This is offered by a private company but many forces ,I know PSNI ,two friends of mine have it, and I would guess the Met provide it in house. So very useful to have onboard.
But on the ground you wouldn't want him distracted from his main purpose for being there.