Even tank commanders have to climb out to use the facilities, get some food, supervise fueling/repair, chat with the local cuties, etc. A deer rifle and a good vantage point are all you need. The Liberator pistol and the CIA ‘deer gun’ were intended for giving to insurgents so they could sneak up on occupiers, fire with the barrel against the target’s body and then escape with his weapons.
The STEN submachine gun was made in more than 20 covert factories in Poland during WWII, with some parts being secretly machined in factories under Nazi control. Cruffler.com has an excellent article on their production.
Resistance against tyranny and oppression is a human right, if not an obligation, and the tools to do so are covered under the 2nd Amendment.
And Staghounds has a post on underground arms factories in Nazi-occupied Denmark; they made over 500 STEN submachine guns during the war.