Never forget that Toxic by Britney Spears is written about Supervet himself.My theory about the kitten is that Baby Daddy had a litter and this one was poorly and, in the course of a conversation around picking or dropping off SB, Jack offered to take it because she saw another opportunity to promote herself and play the role of saviour of the poor and downtrodden.
We know she was tagging Noel Fitzpatrick on Twitter during this time and I am 100% certain that she thought she could get some great media coverage of herself taking the kitten to his celebrity practice and also saw an opportunity to throw herself in his path, eyelashes batting.
So, instead of doing the right thing and getting the kitten humanely PTS (which her regular vet had apparently already suggested), she prolonged its suffering for clicks. And everyone around her let it happen.
PS: I think Noel Fitzpatrick is also deeply problematic, with his experimental treatments on animals. I wish he didn't have a TV programme that promotes this stuff. Or that the Royal College of Veterinary Surgeons would weigh in on whether what he does is humane or meets standards of ethical treatment. IMHO, it's wrong to prolong an animal's life if it causes pain and suffering and Fitzpatrick is changing the culture in Britain, to the point where pet owners think there must always be some maverick solution to keep their pet going, instead of ending their suffering.
Plus, I've heard from several sources that he's a tit to the women in his life.