If a subject is up for discussion on this website, I think it's important that it's predicated on the facts as we know them, not gossip or wish lists. There has been no revelation that Sonia Khan was sacked for leaking and there's no evidence for that. In fact, the few official statements that have emerged suggest to the contrary. From the BBC News website:

"At the meeting with Mr Cummings, Ms Khan, who worked under Mr Hammond, handed over both her personal and work phones, and her phone logs were checked.
Evidence was found that she had been in touch with former colleagues who had worked for Mr Hammond, but not that she had been involved in leaking any sensitive government information.
No reason was given for her dismissal, but the BBC's Iain Watson said it was suggested the issue was about whether she could be trusted to be transparent with No 10."

So let's at least stay on track with that one. Incidentally, though it may not be relevant to the issue, one unassailable fact is that Ms Khan is an avid leaver.