Stuttering in emergency situations

Stuttering in emergency situations i just realized the other day that in emergency situations i am extremely fluent. was at a friends house and had my drink on the floor. someone was walking by and when they were in mid-step (foot about to come down on the glass) i get out "stop, there is a glass there." didn't even realize until a few minutes later that both "st" and "gl" are problem sounds for me but it came out just fine. also a few years ago i witnessed a real bad car wreck and called 911. again, speech as smooth as a babies bottom. any guesses as to the reason why this is? it seems counter-intuitive because stuttering is exacerbated (at least for me) by stress. anyone else with similar (or opposite) experiences?