That Palpatine is trying to reason with Roger at all convinces the droid that he isn't going to try resolving the situation with lightning, at least for the moment, so his rifle lowers just slightly. Now he needs to either find a way to de-escelate without giving up the ruse, or in the best case scenario, to actually convince the Chancellor to let Roger arrest him. Unlikely, but he understands Hondo Ohnaka once managed to capture a Sith Lord, and Roger beat Hondo in a fight once, so maybe it's worth the risk.

With a bit more confidence than before, he responds, "I've been here longer. People know me. They'd trust me to have a good reason."

It's only after he says that that he thinks to throw in, "B-besides! For all you know, there's an entire Separatist garrison on this planet! Maybe everyone here is a loyal citizen of the Confederacy of Independent Systems."