[ He gives a polite nod to the introduction, then chews on his lower lip slightly like he's mulling over the answer to the question. Confidentiality is kind of a big part of working for SHIELD, but he's not entirely sure how much of that applies now. ]

I don't think they're impossible. I've seen portals before, or at least the damage they've caused, so... you think that's why we're here? Portals from other dimensions, maybe.