Maybe so, but was that any excuse for diddling around making spurious calls. If he wasn't worried that she'd use the gun, he could at least have got himself over there to check it out.
I rather think that Jeremy was one of those characters who,at times,was too idle to scratch himself. He'd have been in no hurry as that obviously was his way,and none of us can help the way we are. Laid-back would have been a better description of Jeremy,who never let things worry him.
It was Sheila who possessed the nervous energy,except when she'd had her " soothers ",although speed ( amphetamine ) would have kept her going on the night of the murders.
There's no excuse involved as regards Jeremy.It's the way he was,and sadly,I don't get on with those who don't move themselves,or are alert in any way.It frustrates me and sends my blood-pressure soaring. Those who don't have their wits about them,and Jeremy was one of them,I just feel like kicking them up the behind to get moving. He reminded me of a sloth.

However,as I said,he was " made " that way,and had never had to face an emergency or anything like it so putting it simply,he wasn't prepared for the worst.