Tragically there was virtually nothing to stop Bamber. Despite the low powered rifle -
Sheila - Too weak, unbalanced, uncordinated, drowsy.
Daniel - Too young.
Nicholas - Too young.
June - Too weak.
Add to this they were all sleeping.
A fully fit & ready Nevill could have stopped him. But he was ambushed in bed & received 2 face shots. Then another 2 torso shots out of bed.
Nevill's condition gave Bamber free reign to inflict the 40+ bruises and lacerations in the kitchen. Nevill briefly able to wrestle for the rifle.
Nevill being bare footed in a confined space was another disadvantage.