Question:
Rashi dh Kegon 7 lines up:
"he doesnt get death for no warning given." Why? any way it is BEIN_HASHEMOSHOT and it is only a SOFEK YOM so its perhaps not shabos at all!
Sam
The Gemara's intention is that Bein ha'Shemashos was coming , and not that it already came . (The Gemara uses this expression in a similar manner in Beitzah 19a, where it also means right before Bein ha'Shemashos.) It is still Shabbos when the Milah is started.
Be well,
Kollel Iyun Hadaf