The mechanics of death.

[Pappy13]

Lethal Injection is about as painless as it gets.

[Spider-Dan]

Not when they screw it up:

There is no standard definition of what constitutes a botched execution. For its analysis, Reprieve designated an execution as botched if it met certain criteria. Researchers checked documents and witness reports to confirm details like whether there was evidence that a prisoner made visible or audible expressions of pain, was still conscious after a drug was administered, or whether execution workers had struggled at length to find a prisoner's veins.

That happened in 2022, when execution workers in Alabama spent three hours attempting to insert an IV line into the veins of Joe Nathan James, Jr., a Black man. His autopsy showed puncture marks and cuts in his feet, hands, wrists and arms.. A few months later, Alabama left white prisoner Kenneth Smith alive on the gurney for hours after they struggled to find a vein to use for his lethal injection execution, prompting his lawyers to ask the state to use nitrogen gas to execute him in January.

Lengthy procedures like those were not uncommon, the Reprieve analysis found. Over one third of lethal injections lasted more than 45 minutes and over a quarter took an hour or more.

[masterfins]

Joking aside, I've never known a Vet to have trouble putting down an animal.  I'm anti death penalty all around, so I'd be more in favor of ending the practice.