I think that this is a case that could go either way. What the op needs to do is talk to a behaviorist, and then take a very hard look at things. Clearly the situation as it is has become dangerous. There have been multiple bites that are escalating. That leaves 2 options.
1). Op euthanizes the dog. This way everyones safety is gaurenteed, but leaves the op devastated and wondering what if.
2)op works with the dog, who may or may not ever be safe. They may live a happy life together, or he may bite someone else and be pts. There's no way of knowing.
The situation ks complicated by the living arrangements. Roomates not only mean themselves, but their visitos/family/friends coming over. It only takes one mistake.
Op, I think you're in a tough spot. To me, either choice could be correct. I love my Gambit, but living with a dog with his issues can be exhausting. Do you want to spend the next 10 or 12 or 15 years always watching and advocating? Only you can know when its too much.
I know the joy and the heartbreak of a dog like yours, though not quite as severe, so I would stand behind whatever you choose. I euthed one ha dog, and I kept the other. Both choices came down to me in the end, since I was the one living with it.
I wish you peace with whatever you choose.