No. Nobody deserves to be tortured, no matter how heinous their crime. Torture was something we did in the 1400s. We are more civilized than that.
breathing was also something we did in the 1400s
Although I don't think it's necessary, it's only going to damage their sanity
more. The only purpose is vengeance. Those that are incarcerated for life are incarcerated to keep them out of civilization, and torture doesn't really do anything to help. And if you're insane enough to be a Flash Mober, the thought of torture won't deter you anyway.
However, I don't think there's a need to make execution swift and painless.