Seriously, what the fuck? Can someone explain what was going on in her head?

A female SEI was the leader of a group that I was once a part of. One day, me, her, my ESE exgf, a male, and a female LSE took a trip to Canada. We go to a park and start looking for parking. We spot a muscular looking dude reserving a spot. We pull up:

"Hey let us park here."
"No blah blah blah"
"Blah blah blah"
ESE gets angry. She sticks her body out the car. "You're not a fucking car!"
"Hey, fuck you!" He starts to approach the car.

I hastily made a plan of attack. I was gonna jump out the roof and...the male of unknown type, the driver, pulls away. After we get away, the SEI turns to me and yells at me in anger, "I'm disappointed in you!"

...I wrote a whole story detailing what had happened afterward but I deleted it. Long story short, after some time had passed I got really fucking pissed off and a couple of years later, as insanity started to take hold, I threatened to kill her. After a stint in the mental hospital, I got slapped with a restraining order. I haven't seen or spoken to the group since.

What I wanna know is: what made her think it was okay to just yell at me like that? I can think of a few reasons why but I wanna hear from those who understand SEI better. I've scoured the MBTI message boards, this board and the wiki and the articles, looking for an explanation but nothing so far has satisfied me. This has been on my mind for a very long time.

More details available upon request.