Improvised derringer

Disclaimer: This video was made many months before the Shinzo Abe assassination. There for this is NOT a copy of Abe Destroyer. In fact, Abe destroyer might inspired by this design

A muzzle loading - disposable - electric fired derringer for the citizens of 21st Century.
Can be made from scrap metal and simple electronic components. Small, concealable. Might come in handy if man caught himself in a tight spot.

In the video demonstrate a 2 shots derringer. Theoretically, you can add as many barrels as you like, until it become too cumbersome or too heavy. But to my experiment, 4 is the most you should try.
The more barrels you get, the more complexity will add up. And in a life or death situation, reliability of your firearm is something you don't want to fuck with
Man can wrap some electric tape at the muzzle end to prevent moisture from getting in.