Note to future villains; this is a bad death trap.
Note the pathetic attempt to spiff it up with the "Naughty Dentist" outfit from Dream Dresser and a fancy name like "The Death Machine". We can't hear it, but I'm sure there's some off-screen hunchbacked assistant blowing a 'ta-da' on a kazoo while Doctor Naughty, DDS, makes his presentation. It's still a crappy death trap that's mostly just a pail of water. Rusty, I'll bet. Jeez, Doc; couldn't you afford the Acid Rinse-and-Spit machine? My evil dentist has one.
This? Now this is a death trap, people:
Labelled activation buttons. Gloved hands. Ascots. A cigarette holder (it's off panel, really, I swear). Maniacal triumphant laughter.
And showy fatal stuff. Lots and lots of it.
THAT is a death trap. Or a guest room for your mother-in-law.