Shift Supervisor Drama

So I'm this night-shift worker at the local 24-hour grocery store. Shifts end at seven in the morning, and there's this guy, let’s call him Sam, who's been my supervisor for a while now. He's one of those guys with a very clear idea about how things should run but not so great at actually implementing them. Anyway, last week was particularly rough. We had an unexpected influx of customers late into the night because some big sale happened and everyone came to shop at the last minute. Sam kept telling us over the intercom that we needed to move faster, be more efficient, it's hard to do when shelves are empty and people keep asking for help. I was near my breaking point by five in the morning; I just wanted everything to go smoothly so everyone could leave without complaints. And then Sam did something really stupid. He overheard a customer complaining about how slow things were going, and he walked right up to them, not even bothering with one of us who knew what was happening. 'Look,' Sam started, all grand gestures and fake sincerity. 'I'm so sorry for the inconvenience. I promise you'll be out of here in no time!' Then he went back to pacing around as if it were some sort of performance for us. So that's when it happened. After we finally closed down and everything calmed, I couldn't take it anymore. Sam had this habit of talking about how 'we' needed to be better while he didn’t lift a finger to actually help out during crunch times. As he was walking off, I just blurted it out. 'Sam,' I said, stopping him with a hand on his arm. He turned and gave me that look like he had no idea what would follow. 'You can't keep treating us like we're all supposed to do more while you just walk around and boss people around.' I felt it right away; the air went still as everyone stopped what they were doing and looked at us. Sam's face turned a shade paler than his hair. 'Well, then,' he said finally, turning on his heel and walking off without another word. Everyone packed up quickly after that, no one really knowing how to react. So yeah... I'm not sure if it was the right thing to do at the time or not, but every morning since then feels a bit different now.