Lookout, isn't that rather like saying that someone died in the middle of having a nightmare? Unless there was confirmation from Christine that there was a conversation arranged between them that night -unlikely, given that her children supposedly knew nothing of Sheila's existence and SOMEWHAT cruel for any communication to take place in the home of her adopted mother, who would undoubtedly been hurt, when she had a perfectly adequate home of her own in which to make/take phone-calls- I think any suggestion that such would occur is gossip/hearsay or fantasy because it can't possibly be known unless it comes directly from Christine.
Not forgetting that Sheila was rebelling,and any arrangement for a call to be made to Canada,would further act as part of the rebelling,no matter where the call was made from, as long as it was in earshot of June.
I understand that a call WAS expected,and if it took place,what would Christine have known what followed later ? Apart from she she'd only spoken to Sheila the night before,which I haven't heard whether or not that call took place.
I imagine that June had felt a sense of rejection at having been told about Christine and how she'd interacted with the twins. Not only that,imagine June being told of the kisses and cuddles,etc,to which June would also have felt guilt in not being able to express her love in the same way ( not her fault,it was the way she herself was brought up )
Sheila had found something/someone who'd been missing in her life and must have been overjoyed,though I doubt that June would have shared her enjoyment.In fact,I think that she took the whole meeting,etc quite badly and would have felt more inadequate knowing that Sheila was part of Christine.
This definitely would have had a bearing on what happened that night,I'm sure of it. Even at the mention of a phone call would have been enough to spark things off.