Well, at least Ezra doesn't have to explain that, just work his way through. He assumes he doesn't need to explain why they were there - construction sites are often good places to sleep if you can get in.

"There was this - basement," he says slowly. "Where the construction guys must have broken through. It had these - metal boxes, a weird shape, on shelves. We were being stupid, trying to figure out what had happened, and Zeb opened one.

"It was like," he pauses, hesitantly, aware he's describing something impossible but it actually happened, and Spot already knows he can do impossible things, "these rocks, crystals, with this weird smoke coming off them. When it touched Zeb, it covered him, turned him black like a statue. We tired to help him, but..."

He holds up his hand, remembering the way the black stuff had covered him, made it impossible to move.

"I thought I was dying, then it just... fell off me. I was the only one that survived."