H P,
Agree entirely about gates, and indeed to a degree about 4 secs being enough time to check at the apex.
However, the second hole in the cheese in my hypothesis is that not having sensed the loss of thrust, he glanced at the altimeter at the apex, and took the partially obscured figure to be 3700, more or less what he might have expected, rather than the actual and problematic 2700. I don't think his 4 seconds was used searching for solutions, as I suspect he didnt' realise he had a problem.
Absolute conjecture, I admit, but would explain the continuation of the manoeuvre, with no apparent attempt to escape from it.