I don't think he was touching the top 2 in that race. He was out in 51.1, which is a pace he can handle. Arop went scorching from 500-600 (12.18 second 100). He was not messing around. Korir going 38.4 the last 300, barely decelerating at all in a 1:43-low race is just a different level as well.
To compare to last week's race, Wightman passed everyone from 500-600 running 13.1, and his final 300 was 39.9. So, the top 2 were peaking and ready for this one and not just taking it as another race on the circuit. They showed 1:42 fitness and ran 1:43-low despite running tactically (Arop making a massive move, Korir saving up for an extended kick at 300).