AtD translation: there was a sort of disconnection now in his voice

[Mike Jing]

P552.14-18   “You saved us then, Miles. You saw right into it. No telling
what—”
       “You fellows would have been saved by your own good sense,” Miles
declared. “Whether I’d been there or not.”
       But there was a sort of disconnection now in his voice that Chick
had learned to recognize. “There’s something else, isn’t there.”

What kind of "disconnection" are we talking about here exactly?