Throw away the pills because going all test subject-y is a terrible idea. Instead, use the empty pill bottle to store the gunpowder.
Toss the spent shells away because who needs those.
Afterwards, go over and check what's inside the backpack. If there's enough room for the thermos and gun to fit, store them in it.
Feel free to ignore any of these if you want, I'm just tossing out ideas of things I'd do in that situation.