While in the supply shack Lara will only walk. She needs to cross the building to continue with the game during the level Unexpected Discovery.
There is an Achievement related to this Supply Shack called Avid Shopper. It is unlocked by purchasing all items from the shack. It may glitch and unlock earlier when making a purchase at the shack. 
Starting left, going clockwise.
|Crafting Tool||175 coins|
|Commando Outfit||50 coins|
|Rifle Laser Sight||25 coins|
|Rifle Grenade Launcher||120 coins|
|Rope Ascender||30 coins|
|Pistol Suppressor||25 coins|
|Tactical Shotgun||140 coins|
|Military Rifle||140 coins|
- Personal experience made by "tombraidergirl" (Xbox gamertag); Xbox One digital download version, with day one patch installed.