too many possible answers to say anything — "There was an extended pause as…"
There was an extended pause as I ran a response-tree. Pemulis was zipping and unzipping something with a short zipper. I couldn't decide. I finally had to choose almost at random.
Context
Speech seizes up here as a computation problem: every possible utterance branches into so many possible responses and counter-questions that running the tree exhausts Hal before he can pick a branch, and what finally comes out is chosen "almost at random." The inner Hal is teeming — this is the opposite of empty — but the sheer overload of the interior is exactly what strands it, so that the richest mind in the book can barely push a flat sentence across the gap to his closest friend.