Well, at least Zed's got the satisfaction of making this jerk yell, even as he's trying to put his own fire out. He's smoking, though if there's any odor to burning darkness, it's masked by the strange smell Tom's giving off. He most certainly did not do that, but he doesn't want to let Tom know that. It triggered when he changed, just as rats had attacked and ceilings had collapsed when he'd used his powers earlier..."Do I look stupid enough to set myself on fire?"

And really, he'd love to follow that up with a pulse of darkness, but he's not willing to set himself on fire again after saying that. He's regained a little of his own footing, and he's charging at Tom with his sword.