Not quite what she wanted, but it puts her slightly more at ease, so she decides not to make any further remarks. The little breather doesn't keep her from flinching when he taps the bubble.

"So you say. People didn't start feeling sick right after the explosion went off, either." In other words, how can she be certain? She runs a hand over her face, then through her hair, exasperated without an outlet.

If she refuses, she thinks, he would ask somebody else, somebody gullible or desperate who just might go along. She could try to fight and capture him, turn him over to the local authorities, who have displayed a clear lack of tolerance -- and in the process, provoke him into releasing the gas anyway, accidentally or otherwise. "These tests you're talking about. What are they?"