Day 354/18. Emergency Behaviour

On the way back from a business lunch today and crossing the motorway saw a traffic queue. I stopped for a picture.
What puzzled me a bit was the way an ambulance, presumably on its way to the scene of an accident, did not use the (empty) hard shoulder, but pushed its way through between the two driving lanes.
I assume this is standard procedure, but I've never noticed it before. As drivers we should be aware of this, as I'd assumed that emergency vehicles would use the hard shoulder.
Of course, some drivers were paying attention and moved aside, others sat there asleep with the ambulance behind them.