The shortest isn't the most humane here (as in just dump it in boiling water and call it a day), that's the issue, hence the video Idk how long it takes exactly to die from boiling to death, maybe there's a way to make it faster like some kind of thermic shock, by plunging a super cold lobster into super hot water for instance, but even then I believe the knife cut technic is going to prove to be faster and less painful