There was more than one gun in that farmhouse.Why didn't Neville pick one up,Pargeters for instance,and shoot Jeremy in the legs to put him out of action ? Being that Neville was " the big,strong man " that everyone has described him as being,why wasn't he strong enough to have grappled the rifle from Jeremy and knocked him cold ?
I don't buy the fact that Jeremy wouldn't have shown any marks/injuries from the " violent " struggle in the kitchen. It would have been a fight to the finish between the two men.
No,poor Neville was trying his level best to reason with Sheila,as it's obvious that he was opposed to hitting a woman,particularly a sick one,who he wouldn't have thought was sick enough to open fire.
A young milksop of a man has no chance against a" big,strong" farmer. He'd have knocked the rifle right out of Jeremys' grasp,by immediately diverting his attention.
3 adults ? Come on----------------Sheila wouldn't have been averse to using her " psychotic powers " in order to protect her children.