First Filter
Try and double it up if you can. Meanwhile, if I can find enough scraps of fabric, I can probably make something that will work if we need to deal with something like this going forward.
That's easy, I can even throw in some non-perishable canned goods, maybe in a ripped up backpack? Make it look like someone raided the pantry or a store before the tunnel collapsed on them? Although, if we're going that route can I make a suggestion? Get at least one or two of Derek's trusted guys to explore with you, so they don't question the 'finds' too closely.