Derrick attended a funeral for his friend, Mary’s brother:

“I’m sorry, Mary, it’s unconscionable what’s happening.”

“It’s an epidemic, Derrick! No one’s doing anything. Nowhere’s safe. I’m afraid to leave my house!”

“I know, but do me a favor—store it in your safe, don’t carry it around, don’t leave it readily accessible.”

“But why Derrick? It’s the only thing …”

“Trust me, keep it locked up.”

“Alright.” Mary sniffled.

Derrick released his self-replicating nanites, programmed to dismantle every domestic ranged weapon, causing many to explode instantly. Needless to say, it also had a latent culling effect for future generations.