If Dora hadn't continued speaking, Spike may have pointed out how stupid the Heads would be to return powers and weapons. It was true, really; but he wasn't completely certain that they weren't stupid enough to make such an egregious mistake. They had been stupid enough to make one mistake... and at least one of them responded to provocation on the network. Even without weapons, maybe they'd underestimate the power of certain magics, return those they didn't realize could be used as weapons.
There were far too many ifs and maybes for Spike's liking, but he appreciated that the odds weren't completely against the captives. Very near to it, yes... but he liked to think that was beside the point.
For a moment, skepticism showed in his expression. He wanted very much to believe that Dora wasn't just being egotistical - that they really didn't know her as well as they thought - but he'd believed the same of himself, once. Then they'd plastered pieces of his past, most of them real, on the television screen. Maybe they still didn't understand his level of determination or just what kind of tricks he had up his sleeves (or in his skull), but they were definitely too close for comfort. Far too close.
Even so, Dora had something a little trickier to claim - something that easily turned his skepticism into a smug sort of smile.
"You make it hard to be a pessimist," he said, intentionally more monotone than such a statement should be presented. "Maybe you should go ahead and make some. Just... so it's there if we need it."
Spike saw no reason to miss the opportunity for a deadly weapon, poison or otherwise. Anything could be useful, especially when planning something which had the potential to get someone killed. Or electrocuted, if that was still the captors' preferred method of defense...
He saw the awkwardness in Dora's posture and chuckled slightly, shifting his weight so that it wasn't all on one arm. The action caused a slight hesitation, but he played it off as if caused by... anything other than pain. "They're overconfident," he decided. "They know we have guns, knives, and magic... they've seen us use 'em against Reavers. But they have no proof that your... skill... was underestimated." Of course, it was speculation at best; but it made sense in his mind.
Spike was quiet for a brief moment, considering whether he should say something personal in exchange for her offering. It wasn't that he didn't trust her by now, it was more a case of being hard-wired not to share secrets - especially those which revolve around strengths or weaknesses. Giving the Heads ideas wasn't exactly top on his list of things to do, either, should the shore prove to be bugged just as the rest of the island. So he decided against a personal revelation of his own and, instead, chose to redirect the conversation.