Yeah, sometimes, one don't bother being subtle with the traps.

Wait.... when did he get a masterwork mop?.... or is the navy just mass issuing masterwork mops?

.... so many questions.

They take the cleaning very seriousely in Logue town base. So the janitor is granted a masterwork mop, plus one spare in case the first one break.
The third one is just there so that soldiers can have a improvised weapon handy if a surprise attack caugh them unarmed.

Zoro took the three mops at once.