Beutifully written and insightful...
Thank you. :)

I'm sure Buffy would squash that unworthy impulse
Oh probably. If I recall correctly, my main aim with that line was to show how Buffy is finding herself leaning on Faith - and Faith is of course already betraying her. Just a bit of extra pain! (Also the situation reminds me of 'Selfless' - and trying to kill Anya *does* almost cost Buffy Xander's friendship.)