If he has enough power to climb up and away like that then to me it just looks like the T/R is not up to the job. We are always flying to one limit or another and on this occsion it was the T/R limit of thrust and it's ability to hold the nose straight. As others have said if you pull any more power beyond that it is going to end in tears.
Is LTE just a myth put about as an excuse for a poor T/R covered by a whacking great big fin?