Sophie's been pretty mouthy and bitchy about both Kris and Noirin, so it's only fair that she get some back
Personally, I can't stand any of them - they represent every shallow and trashy value in society nowadays.
I wasn't convinced anyway that Tom would be interested in Noirin for anything other than a quick sh*g, since that's all she's good for.
Kris and Noirin have lost out on megabuck deals (him with Sophie and her with Isaac and Tom) so I am viewing their supposed romance as a mercenary and cynical way to get some media interest. Anyone who thinks otherwise must be seriously naive.