Was his jacket zipped when he first saw Martin?
For the love of God! You're not going to see the gun even if he's not wearing a jacket. You put a small frame gun into a waist band holster and you're not going to get what is known as a "print" which means a recognizable shape of a gun beneath your shirt. That's what that type of holster is DESIGNED to do. Seriously...you need to bone up on this stuff, Luissa...you're ignorance is showing!
If it there was recognizable shape underneath his shirt in a waist band holder than how would he know he had a gun if his jacket fell open?
Sigh, you WOULDN'T know he had a gun...that's the whole idea of a waist band holster!