Ah, thank you Jos.
It occurred to me that she hardly dares be seen to 'repent' while she's still in Syria. Even if she did return to UK, the fundamentalist Isis supporters might attack/target her for rejecting their cause.

She could also be seen by them as a risk, if she gave us information about terrorist activities etc. She'd be a 'marked woman'.

This might explain her cool, hard tone of 'not being fazed' by the severed heads etc. She's wary of reprisals and vengeance.