I remember the first time I saw Batman murder a villain in cold blood. It was the happy go lucky 1960s Batman if you can believe it.
Adam West murdered a hapless goon or three before he informed Burt Ward just how he could kill a few himself. It was chilling to see how matter of fact Batman and Robin could be when taking a life.
The Penguin had accidentally added radioactive hard water to his dehydrated goons to rehydrate them. One good punch and they would blink out of existence. Where did he think they were going? Batman is the world’s greatest detective. He had to know.
But if Batman is willing to inflict inhuman torture on these poor goons, just imagine what hell they must have been put through when the Joker used his high tech torture device to suck every last drop of water out of these hapless humans to turn them into dayglow piles of pink and yellow dust in the first place.