What happened when the bulk of the fans got to the gas holder corner - did they keep the traffic lights on?
Just one lane out of gate 1 for cars (all from the west car park), with pedestrians alongside. Those who obeyed the signs and went round the long way cut across the cars leaving gate 2 and again at gate 1. They put cones out to make a vehicle lane out at gate 1 onto Alan Turing Way (so forcing cars already in the two lanes on Alan Turing Way to merge into the outside lane - itself a hazard) but then after the lights, anyone in the right lane wanting to turn into Bradford Road then has to cut across to the inside lane, another hazardous move.
With all the pedestrians cutting across cars in various places, and the newly-created conflicts between pedestrians and cars and between cars and cars, this really is a poor idea. Whether there was really much improvement in getaway time for cars seems doubtful.