The next time he tirades? I don't care if you're in class and the prof is talking, stand up, look at him and say, "I need to step outside. Please remember we're professional adults when I return." And walk the fuck out of the room.

Nothing, and I mean NOTHING, is keeping you there. This is college. You don't need a hall pass. And if your professor gets upset with you, tell him/her that stepping away is for your health and so you don't lose it on him since you respect his/her class too much for that kind of drama.

And when he throws out random tangent questions? "That's not relevant, let's stick to the subject at hand."

And when he starts screaming at you because he's a child? In a calm voice, raise your hands and say, "We're all adults here, let's keep this on an adult level, please."

And you should talk to your professor. Tell him/her that you're paying for this class and he is making it difficult to learn anything and it's making you want to stop coming. I can't imagine you're excited about that class coming around every week.

In short, walk away when he's damaging you, but the rest of the time, stay professional and remind him that he's a fucking adult. Ugh. I do not understand why professors let poison like this infect their classrooms. This isn't high school anymore, dammit.