Just be careful when in dangerous situations. If you have doubts about someone's intentions, act accordingly...even if it means rudely distancing yourself from them or causing a scene.
I had a situation once a long time ago where I was approached by a very good player to play some 9-ball sets. I had seen him play a couple days prior to this and knew he was a professional caliber player capable of putting multiple packs on me. I told him as much and that I wouldn't play without getting a huge spot, i.e. it likely wasn't worth his time. He agreed, and gave me the orange crush in races to 7.
He was dumping so I easily beat him the first two sets. We doubled the bet.
He tried to keep the third set close and get me at the end by leaving me a very tough shot, hoping I would miss either the ball or position. I made it even though I usually can't pull of that kind of shot and he said, "you don't make that shot". I said, "you're right. I usually don't...but I made it that time didn't I". I ran out the rest of that rack and broke and got to the five in the next to with the third set.
I had to leave in about 45 minutes so I told him I had time for one more set and that we could double the bet again if he wanted to. This was not good enough for him. He wanted to more than double the bet and regain all his dumpings and come out winner on one set! I said no to this huge bet increase, saying that we can raise the bet to double or nothing for what I'm owed...but not higher than that.
He started to get angry and up in my face and said something to the effect of, "I'm going to wait for you out in the parking lot and kill you". I could see that he wasn't joking and that I was in a tough spot considering nobody else had heard this. I took about 5 seconds to evaluate the situation and then I raised my voice and started yelling at him for all to hear.
I said, "What is your problem?!? Are you threatening me? I came down here to play some pool...not get threatened. When I lose, I pay...I don't whine about it. I didn't come here to listen to your gangster talk and be told that someone's going to kill me in the parking lot. Perhaps I should walk down to the police station and let them in on your little plan. What do you think they would say to that?"
He turned beet red and left. I was warned by an older guy that he was an extremely dangerous guy (read pimped out Impala) and that I shouldn't have angered him. I had to do something.
To this day, I think I did the right thing. I heard he died a while back. That's the first guy who died that owed me money.