Minutes after Neelix chucks Michael Jonas into a plasma fire, thus disintegrating Michael Jonas, he’s cracking jokes with Tuvok. That’s like Khan Noonien Singh levels of cold if you stop and think about it. What does that jovial exterior actually hide?
The only ruthless thing here is how ruthlessly efficient the Voyager writers were. A multi-episode crewman traitor arc without any of the messy logistics of determining if or how they could confine him to the brig for years? Jonas didn’t even get the Suder treatment.