According to the attorneys present at this workshop, both prosecuting and defense, uttering the words “I’ll shoot” can and usually is used against you. They say it’s not hard to convince a jury that your intent was to kill someone. In other words, they will turn you into a blood hungry gun owner.
Best to stop after “Stop, I am armed.” If they’re armed you should be telling them to drop whatever it is they’re armed with and “ask” (tell) them “don’t make me do this.” This statement takes the onus off you the defender and puts it back on the offender. They knew the consequences of their actions and continued the attack.