I get where you're coming from, it's just from the evidence we know so far, gene was on the other side of the house, either heading in or out.
If in, how would he have heard her?
If out, why leave the house without his cellphone and calling 911?
Ie, if LE reveal his phone was in his jacket pocket in the mudroom and he didn't reach it because he fell before he could, then we could infer that he was trying to help Betsy.
If his phone was in the bedroom, then not so much.
Unless someone moved their bodies post mortem, placing them in the positions they were found in.
Not saying this is any more likely than they both separately died of natural causes, but IMO and JMO nothing in this case feels 'obvious'.