What would you have done?

It was hot when I was planning on leaving town this afternoon. On reaching the bus terminal I was the first and only passenger. School was out but no-one seemed to be in any hurry to go home and I knew it would be a while before the bus filled up, which would entail sitting in the dark and the dust and the heat and the fumes that are integral to the building's design. (Whoever designed the terminal should be made to sit, interminably, on a bus that is waiting to fill ) I digress. I decided to go back into town and buy a soda from the nearest rum shop with a small veranda, that offers the chance of some breeze, a place to people watch and a nicotine opportunity. Now, I know this is a rum shop and can get a little rumbustious but everyone is friendly and we are accustomed going there and being outside is different from being inside. I buy the soda and take myself outside, sip, inhale, relax. Wonderful. It was only on hearing a raised, male, repetitive voice, from the opposite end of the veranda, that I realised all was not well. He seemed to be remonstrating a beautiful woman for something she had or had not done. When he pelted his half full drink in the drain, by way of demonstrating how vexed he was, I knew this was turning nasty. Quite a few people passing, slowed and turned to watch as he put his hands around her throat and shook her hard, but none stopped. He propelled her down my end of the veranda at the point where I was really hoping someone from inside would hear what was happening and come and restrain him. He was big, I am small and his wife/ girlfriend, whilst taller, was mute and passive, as he pushed hard and prodded hard and cursed harder. I knew where this was going, you could see the extreme anger about to surface, like milk when it is about to boil over. I felt like I had to catch it before it was too late. The veranda is small, I had my back to the wall and they were about six inches in front of me. He had her pinned to the railings. I cannot deny that I did want to up and leave at that point, but it just seemed so wrong. I heard a very small voice say "Excuse me", so I tried a little harder and shouted, in my best 'you are a very naughty child' voice, "EXCUSE ME. " and I hoped it would provide a little diversion for her to escape while he focused, as he did, eventually, on me. The response was what I should have expected and, thankfully, nothing more . "SHUT YOUR @#%&IN @%^*" Ah, yes, well, I did as I was told but not before going back into the shop and alerting them to what was happening and then, quietly, headed back to the bus. I was shaken. I have no idea what happened after I left, perhaps everyone laughed and ended up friends but I don't think so, was it a stupid thing to do, drawing attention to myself in an already volatile situation? Did my actions change anything? I doubt it. I write this post having read this just recently, I hate any form of confrontation and much prefer to live a quiet life but sometimes, I have to speak.
What would you have done?