Seriously though, I find the fact the A) You remained seated or holding on to a chair and B) You did not immediatly follow your instinct and jump up to establish Ma-ai when you felt threatened disturbing.
Certainly something to look at in your practice of Aikido.
Hmmm - not so sure about that.
Jumping out of a chair...or just jumping away could well have provided all the trigger needed to escalate a verbal confrontation into a physical one.
What is required is a controlled and unthreatening adjustment of position so that one in position to deal with any attack the microsecond before it commences.
If you can get to a position whereby the agressor is vulnerable and he doesn't know, then you hold the upper hand.
In aikido parlance...this would translate as do not disturb your uke.
eg.Dont jerk your wrist away as uke grasps...allow him the luxury of this grip before using your response. That hand is no longer dangerous while it grips. Move calmly into position and then when you have perfect position....WHAM!! 'Kill him'...(to borrow a quote from one of my major influences'.
Now that is something to incorporate into your practice!
As for controlling adrenaline dump...accept it. It is useful for triggering fight or flight ....the day you lose it completely you are in trouble.
Pressured training can help familiarise one with it to prevent it hampering performance.