Don't know about the 757 AFM or the operator's own Ops Manual rules (willing to hazard a guess reversing is non-SOP though). However, aside from whether the manoeuvre in itself was or wasn't a good idea, quick thinking, safe/dangerous etc. etc. etc. my immediate reaction is more to do with how bad the CRM must evidently have been there. I mean, look at the time between stopping and when the reversers unlock - there is no way this could have been a two-crew discussion. In my opinion, CRM should have moved on from the days where one guy takes an immediate decision to do something out of the ordinary where safety is clearly not on the line.