The appearance of a Confederate Battle Droid, especially one as changed as Roger, pointing a rifle at him and demanding his surrender, is a surprise to be sure, and an unwelcome one at that. The droid is a complication that Palpatine had hoped to avoid. They feel alone right now..it would be easy to slip out his lightsaber, leap forward and silence this contemptible B1 in a single bound...

Or would it? Roger is changed, and Palpatine doesn't know how much, but the extra limbs alone suggest attempting to destroy Roger might spill out into the rest of the station. Not an outcome Palpatine wishes.

So for now he simply drops the kindly old facade and lets a cold imperiousness settle into his features.

"Your fear betrays you, droid."