There's a difference between sticking to the letter of the order, and actively being malicious about it. It doesn't effect his loyalty (unless he agreed to corruption), but it shows he seems to oppose her decision, it's hardly a jump to suspect he could go to opposing her will. Lea get further to shaken off Nemesis than Cait Sith. Hell there aren't many mayor characters that have been corrupted. He gets close than Aurora and Maeve, but that isn't saying much.
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Did he ever get truly malicious about it, though? The closest I can think of is shredding that security dude's leg, and even Harry isn't certain that was cruelty so much as just Getting The Job Done. They needed a distraction, he distracted, and everyone lived. Something tells me Sith's usual idea of distraction is "nobody responds to the alarm if there's nobody alive to respond."
But all in all I just don't think agreement is something Nemesis needs. It gets a chance, it takes you.
