He tapped out? What if this happens on the street? , this is good practice. If you talked to your instructor about this and you voiced a legitimate concern about getting injured, I would say "bail out" of that school and find another place to do BJJ.
Maybe, just maybe this would be a little different if he would then go over some techniques and concepts that you might be able to use to protect your self/counter the "technique"; Then insure you have time to develop the application before you are thrown back into what sounds like a constant situation with these guys with no effective way to defend your self.
When ever I hear "what if this happens in the street" I say to my self "What if I dropped an air conditioning unit on you from a couple of stories up while your going out to lunch?" as I would make sure to use my legs and not my back to push it over the edge thus ensuring clean technique. There is another question I always ask too, "What if there are unicorns involved?". So many what if's...
Slamming is a pretty quick way to injure someone, It sounds like the instructor takes little responsibility for happens on his mats and ignoring a request too keep it safe sounds very unprofessional.
As far as your rage choke rampage goes, I would take this as a lesson. If you can come away with a conscious awareness on what takes you over the edge then you can recognize it and know what it feels/what it looks like. It's human nature and not totally out of place but I would consider yourself extremely lucky. If it happened anywhere else things might have ended up worse for your.
Most people don't have a clue what will push them over the edge. Rage, happiness, sadness and all other emotions are the foundations and pillars of what makes us human. Many people think rationality and intellect will allow them to stay immune to the effects of emotion, "good luck with that" is all I can come up with.
If no one of this planet would be able to face regret I can't imagine how different life would be. Quitting like this, I'm going to say you will regret it. Quitting is fine many people don't do it soon enough, but not like this not from feeling bad for yourself. Not loving it, now that's a respectful reason- it sounds like you do , so don't
For you - remember it - it sure can effect you but it doesn't control you. Now you know about it and it's not invisible sneaking up on you is going to be difficult.