Finis did not like the situation he was in currently.
Firstly, he was manhandled by an islander of all people. Secondly, this review surprised him. He did not like surprises. Thirdly, while he at first appreciated Viola's bravery. She was way to energetic. It would was the worse thing in the world, but it simply compounded the rest of the days worries.
However, more than any of that, was the sheer amount of unknown information. He had no information on either Viola or the sergeant, which could be critical in the future. He also had no idea about this ghastly figure. The fact he could not even tell if it was a ghost or criminal infuriated him further. There was also the strange report by Viola, another unknown variable. I could be related to the ghastly figure.
Finis keep his frustrations to himself. While the others escorted Viola and handled the social interaction part of information gathering, he would search within the walls for information regarding the sergeant and the ghastly figure. In order to avoid more trouble with the sergeant, he would first start with legal means and see if more covert digging would be required.