I remember some jokes around it being about cell receptiveness. Like their receptors don’t react to taking pigment the same way they don’t react to the anesthesia as well. If so, it would likely be a genetic trait, so the more natural red heads that have extremely low pigment may require more anesthesia to keep them under. But I’m no doctor, and most of those jokes had to do with their soul not being around to pick up the call 🤷.
It’s when Vin Diesel and Paul Walker pull up to a red light next to each other, and no one see’s what happens next