If I am in the middle of Shmone Esre and the Minyan is saying Birkat Cohanim, should I stop praying until they are finished or go through it?
One in middle of Shmone Esre when the Minyan reaches Birkat Cohanim should stop and listen to the Bracha with Kavana. Same as Kedusha and Amen Yehe Shme Raba, as said in Shulchan Aruch OC 104:7. Though regarding Kedusha and Kaddish some Achronim wrote that one who wishes to continue davening may, here everyone must listen since there are opinions that Israelites listening to the Bracha are also doing a Mitzva from the Torah. This person should not answer Amen, unless he is in Shmone Esre where the Chazan is - the end of Modim, then he can answer Amen to the Birkat Cohanim itself, but some say not to answer Amen to the Bracha the Cohanim make before it. See Mishna Brura 128:79 who wrote that on the Chazan. Rabbi Eliezer Melamed