I’ve never gotten the roaring, but I did once see red. Like you, I thought the whole “seeing red” and “roaring in the head” think was just literary license, but I organize the copwatch program here, so I have a lot of contact with some very obnoxious pigs on a regular basis. After one particularly unpleasant interaction (the officer was eventually given an unofficial reprimand for demanding identification as an intimidation tactic), I stood with my arms crossed beside the person who had been the target of the police harassment while the cop sat in his car, staring back, each of us waiting for the other one to leave. Eventually the cop rolled down his window and said, “Why are you looking at me like that?”
“Like what?” I asked.
“Like you want to pop me one in the face.”
When I was young, my father would tell me to “wipe that look off your face before I wipe it off for you,” and if I couldn’t get a neutral expression up fast enough I’d get a cuff in the head. This interaction with the cop triggered the most incredible rage, and I began literally seeing red. It was terrifying, the whole world turned shades of red, like I was seeing through a sheet of blood. The shock of it was enough to cool my anger, fortunately.