With really high ambient air temps. and more so on the runway. often it can be like flaring into a vacuum as the engine performance just stagnates. RAF Harriers use demin water to boost take off performance but I'm unsure if it can be used for landing as well.
Aviation Fuel - Jet Fuel Information This explains it reasonably well.
His aux doors(also known as Puffer Ducts or Suction doors) were sequentially opening as he descended the last 30 feet or so, and so clearly he was asking for power. Look at the video and you will see the doors (more like small panels really) are just beside and aft of the intakes on either side and at the point of impact they all close again. This may be a feature of the engine collapsing on its mountings or sudden lack of demand from the cockpit or more likely the inertia switches shutting everything off . The Puffer Duct doors are simply spring loaded so will automatically snap shut.
They are alwaays wide open when the Harrier is hovering.
As far as the MB seat is concerned it has some clever features and is a rocket seat
with active directional control. The biggest problem is nicknamed MDC Spatter where the explosive detonation cord built into a lead triangular pipe and moulded into the canopy above the pilots head, shatters the canopy into millions of shards of perspex type glass. Another system is called FLSC (Flexible Linear Shaped Charge ) which is also embedded in the acrylic moulding of the canopy and does exactly the same as MDC. All flying clothing including the helmets( the visors of which automatically
snap shut and tight agains an MDC guard across the top of the visors) for aeroplanes using MDC canopies have special re-inforced areas on the arms, shoulders, upper thighs, and chest. At the end of the day, this aeroplane was now of little or no value to anyone as an aeroplane and his decision to abandon was the only and correct decision. The BOI (Board of Inquiry) will publish their findings and the Pilot will have probably have already gone out of the R.A.F. now anyway.
Very lucky on the day.
Additional background - the seat used in the Harrier is the zero/zero variety and does not rely on forward speed or altitude - hence the need to destroy the canopy before the pilot on his seat is driven upward through the canopy during the rocket phase of the ejection .