Hello,
It's up to your GM to contain the munchkin. We stopped trying to put in all kinds of extra controls and extra hard rules in the role-playing game when we realized it would triple the size of the book, and only thwart a handful of rules lawyers.
Just remember that what benefits a player-character can also benefit a hostile NPC, so if your munchkin thinks he can be special by using his Patient Trait on any old 5-second Skill check, so can the enemy spotter lining artillery up with his head.
Thanks,
- Herbert Beas