Who was witnessing what unfold?
Who supposedly used the phone to call Jeremy? Clearly she means Nevill. She is asking why Nevill would call Jeremy instead of taking action himself.
It makes far more sense to grab a shotgun or knife than o call Jeremy and hope that for the 15 minutes it takes for him to arrive that Sheila won't do anything. oreover, why would Jeremy have better luck unarming her than Nevill would?
If Jeremy had some special relationship with her where he was calming to her that would be one thing but the reverse is true. The calming one was Nevill and Jeremy caused angst. Indeed the main episode Jeremy supporters love to use of Sheila not knowing who anyone was for hours and numerous people being unable to calm her down resulted in her instantly recognizing Nevill and becoming calm in his presence. Her doctor said he had a calming presence even and was her rock. So he would have been the one most likely to be able to calm her down and he was already there. He would have no reason to call Jeremy. This is one of several problems with the call claim.
1) How would he get away from Sheila to use the phone
2) Why would he leave his wife and the kids in bed to face Sheila alone
3) Time was of the essence so why would he call someone instead of trying to disarm her himself or to arm himself and then confront her
4) Why would he call Jeremy
5) The evidence establishes the event started with the killer shooting the parents in bed which conflicts with the claim of the phone call to him before any shooting took place.
All of these things are problematic and that is without even considering the evidence that Sheila didn't do it.