Chopjock.
It is not uncommon for an air ambulance to land and drop off it's paramedics (to start assessing and treating the casualty, secure him in the stretcher etc) then depart again for various reasons e.g to land in a place better suited to loading the stretcher or, as in this case, burn off some fuel.
Air Ambulances tend to standby with a pre-decided fuel load based on what they might reasonably expect to have to do - therefore, if they get a job that is a close to base, thus burning less fuel to get there, they might end up a little over and have to burn a bit off.
As for "red-lining it a bit" to get the job done - that's not the way it should work - as another poster said - every flight is potentially life-saving so what would happen if they did that every time?
As for dropping a paramedic or some equipment - who looks after the patient in flight and what happens on the next job after they've dropped this patient if one of their paramedics and half their kit is in a field miles away?
Hope that information is useful to you.
OH