First off, make sure you're not confusing the "zone" with losing control. Anyone who's fought seriously knows this place of mental peace. Pain being reduced, faster responses, etc. Basically an adrenaline dump. As long as you can keep you head in such a situation, you'll be fine. How? Practice, Practice, Practice, Practice, Practice, Practice, Practice, and more Practice.
As long as you stay out of control of your actions, you'll never be at your best. I'm sure you know this, but I have a reason for bringing it up.
Your no mind/blank mindset seems more survival based and not retaliatory. That said, the auto-pilot reaction is a great way to get stomped and put out even faster than keeping your cool and being in control of the situation. A human's natural weapon is his mind. Going on auto in a situation like this is akin to fighting with a stick in a fire fight.
This "nobody can hurt me", "I don't feel pain", "eliminate the enemy" talk makes me wonder if you've ever been humbled. I mean put in positions where no matter what you did, you were outclassed. When this happens, you'll realize your best bet isn't going feral, but doing the exact opposite and controlling the situation.
Also, realize what your doing at the moment. You're not in a survival situation. Street-fighting requires a completely different mindset. MMA != Street-fighting. You should be either sparring or competing. Not trying to off someone. That said, there is no need for such a reaction at anytime. If your getting tooled, either suck it up or walk away and train with someone else who's willing to train, instead of stroking their ego.
Personally, I think aggression is over-rated. I perform better calm and collected, not "angry" like my old football coaches used to spew. I know when to take care of business and when to avoid stupid situations.
Hope this helps.