I'm surprised you should have been gulfed so easily, said Tuppence scornfully.
Tuppence was maddened and surprised by the fact that the other person was gulfed so easily.
mnli hypothesis: Tuppence was maddened and surprised by the fact that the other person was gulfed so easily. premise: I'm surprised you should have been gulfed so easily, said Tuppence scornfully.