In another lifetime, I had to break up with a young man I had dated for a month or two. I thought I'd ask him over for coffee and tell him then. It was winter.
I had never done this before. Without telling him my plan, I asked a man how to break up with R, and he said, "Oh whatever you do, don't ask him over for coffee!" He then explained that R would appear at my door, I'd let him in, and then with it being winter, R would have to take off gloves and a heavy coat, boots, scarf, a hat. Then we'd sit down and the intent of the conversation would become obvious. R would have to collect and put on boots and hat and heavy coat and gloves and try to make a graceful exit.
FWIW, friend said to ask R to come on over. I should meet him at the door with any of his belongings, tell him at the door that it was over, and if he wanted to punish himself by listening to the reasons, then it would be R's decision to walk up the three flights of stairs, take off his winter clothes and discuss.
The mall idea sound fine. I just have especially poor instincts with this stuff.