"So you see, this blade is so sharp it can literally split atoms in half! Now watch me cut these hydrogen-atoms... Nothing...cause you see..."

puts on lab coat

Manifests a whiteboard out of thin air

"For nuclear fission to be dangerous you need a very specific setup, most important of all right next to the material used you need an enclosed space, or it will be hard to reach critical mass. If you put this highly radioactive material in an enclosed sphere, like this one, which can reflect the electrons back at it, given a short amount of time it will create a feedback loop and reach critical ma..."