How about this? Take out the pin, hurl the grenade over the wall, and hide under the box.
Box are not big enough.
Pull pin throw grenade then do a grenade jump as it blows, after wards get the ammo.
As you open the box and take the ammo, you feel watched by someone or...   ...something...
You take the ammo. Where should you go? To thew west you hear waves, to the north you hear the sounds of a forest, to the east you hear guns being fired and shouting, and the south is where your base is, and where you just were, but you can go back and get more ammo. And should you search the dead guards? They have guns and ammo, and may have other important items *cough* carrot *cough*.
