"Given I haven't had dysentery in the nearly three years I've been here, I'm pretty sure," Tommy answered. "But we can go with boiled water if you want."

Don't be an idiot, kid. Especially given the fact that the second Tommy stops talking there's a brief blur of color (green like the tank-top he's wearing), and a burst of wind. Mostly all of that goes along with the fact that Tommy is, in less than the blink of an eye, standing directly in front of Dustin, sipping out of the very glass he filled. Then he raises an eyebrow as if to say 'see, i trust it'.