“Kitten” also revealed that the reason Skinner has been “Assistant Director” Skinner for the past 25+ years is that he supported Mulder and Scully in their attempts to chase aliens and monsters with badges and guns.
He told the agents that he was proud to have supported them and that they saved his life more than once.
The events of “Kitten” were traumatizing enough that he feels compelled to do what he can to expose the government’s previous and ongoing experimentations with gases, career be damned if that’s what it takes.
If that’s not heartbreaking enough, Skinner spent the episode dealing with his Vietnam demons, not the least of which was how he was forced to shoot a 10-year-old Vietnamese boy in the head when he walked up to Skinner’s unit wearing a bunch of grenades, earning the nickname “Babykiller” from his comrades.