See I think the opposite, I think Shauna was totally wrong, other than it was wrong for them to to try to get nas to pick them over Demi. Sophie and Leanne should not have done that. It was shitty.
But this new rule Shauna has randomly invented where if you come in, spend less than two weeks with a guy you like, and he is chucked out, you should immediately fuck off out of it with him, is not ok in my eyes.
The over whelming majority of them don't leave with their partners, even when its being going on much much longer.
It's clear she has an issue with Sophie, even though she tried to keep her in, because she stated twice that she felt Callum put Sophie first above her. She then refused to tell Callum what she said to Sophie and got angry and stormed off. Because she didn't wish to tell him she'd basically told Sophie to leave and that she shouldn't be there.
I think she fundamentally likes Sophie, she is just hugely insecure, doesn't like what she perceives as Callum putting her first, so her solution is to try to talk Sophie into leaving, as that would solve her issue.