Impressive but not that tremendous. He is, at his best, capable of the first two reps with zero rest so he should not have been shattered when he began the third rep. Four minutes is quite a long recovery from what was clearly a sub maximal effort. In a strange sort of way it would have been more impressive to start with the 1:51 and finish with the 1:57! (Not that this would have been a sensible workout but it would show him holding a reasonable pace under conditions of real fatigue.)
Also you need to factor in things like the weather on the day, was he paced? what training had he done the few days prior to this session? etc., etc.