The doorway opens up to a fork where both paths lead to all three howitzers. Going down the left path, you encounter a Chinese sniper. Once on the lowest level, hooking back around will bring you to more Chinese soldiers as well as a health dispenser and ammo dispenser. However, if you keep going forward you will find a path that leads to an artillery gun and a bunker filled with Chinese soldiers and additional supplies like health and ammunition. The path continuing on leads to the next artillery gun and bunker. It's the same drill as the last gun, but there is also a Chinese inferno unit thrown in the mix. From there, the next artillery gun is straight ahead and down a hill. There is another bunker with Chinese soldiers inside with another inferno unit.