No one seems to have yet noted that the starboard engine was not shut down at the time the evacuation began. The engine exhaust can be seen to be blowing smoke behind the plane in those videos that are taken from the port side.
In one video that is taken from the starboard side of the plane (which can be seen on the Daily Mail's website - sorry about that) the R4 escape slide can be seen to be deployed after 30 seconds or so, but can be seen to flail around in the exhaust coming from the starboard engine.
Also, the R3 escape slide can be seen to twisted towards the tail of the plane in this photo, most probably by engine exhaust but possibly also by water pressure from fire hoses. No one can be seen to escape from R4 or R3 in the Daily Mail video, which is unusual given that the cabin crew would normally direct passengers to an escape on a slide on the opposite side of an active fire.
