I don't think it was stalled.
I also don't think the LH engine was secured.
Maybe it was still giving some power but not as much as to be equiv to feathered. Auto feather didn't kick in because they didn't get neg torque and they didn't realise that getting 5-10% torque is worse than feathered.
I think they lifted the nose because they thought they were going to hit those flats.
Speed came back and went below Vmca and then they ran out of roll/yaw authority.