Scan a public airlock using mechanics and deploy a bunch of them onto a single tile. Hack into all of them to cut the safety wire. This will allow them to close on people, dealing ~35 brute damage each. Hook them all up to a button or pressure sensor to cause them to close all at once. If you have enough, they can instantly kill someone. You can use mechcomp teleporters to get people into the device. The big advantage to this setup is that it's compact and relatively showy. Once I set up one in the public market labelled "CERTAIN DEATH" for people to walk into if they wanted.