J,as your profile does not indicate you are an aviator, I`ll keep it simple , hopefully..!In normal flight the aircraft flies in a balanced condition..ie Lift=Weight; Thrust=Drag, at constant speed; also, assuming the aircraft is trimmed correctly, it will be stable about the 3 axes,longitudinal,lateral, and directional.
Assuming, in this case,following an engine failure in a turn,if no recvery action is taken, the a/c will yaw, and roll further into the turn; if the nose goes down the speed will increase,drag from the failed engine will increase, further increasing the yaw and roll. The aircraft will now increase it`s roll/yaw,but if the a/c was trimmed initially at 180, and speed increases to ,say 220, the rate of turn will increase as the a/c tries to return to it`s initial trimmed speed, but it will have increased it`s "g" loading towards the centre of turn. If the situation is allowed to continue, the speed increase and loading could inhibit further control and lead to overstress/break-up , if one tried to pull the a/c out,as it would also be `asymmetric`,or `rolling` `g`.
So, it is a `must` that in this situation one must `level` the wings first, reduce power to assist, if necessary, and then sort out the failure....
The procedure is essentially the same whether it is a Seneca or a 747. Don`t let the aeroplane get away from you, and if you are going to crash, then crash under control..........!