"Uh," Seth answers, frowning up at him in confusion. "Yeah. It, uh, it depends. Longer with smaller areas. Few minutes in total, at most."

He walked through a lot of walls when he escaped from the base, which had left him completely drained, and had mostly been fueled by desperation. But he's not all that great with extended phasing. When he just has to get through something, it only takes a few seconds. If he's stuck in something for longer, like just now with the rubble, it takes a lot more out of him.

"Why?" he asks warily. Something in Daniel's question makes him worried. Not to mention the discussion of grenades.