Don't know about the PLI on 757, but as you and JT have said, Power and attitude plus Rad Alt would have saved the day ...........BUT, and a BIG BUT, this is ARMCHAIR diagnosis, and as you can see Flight Detent would have got it wrong relying on GS readout from the FMC - even now from the armchair!
I tried to put myself in their place, with all the conflicting, illogical warnings, noises, ATC inputs, stick shake etc, and I HOPE I would have managed to sort it out - but I do NOT know. It must have been a pretty horrendous cockpit to be in.