Adult Fear: Mulder has to turn the gun on Scully, his close friend and partner. And wasn't able to stop pulling the trigger until Scully distracts Modell. Fridge Horror sets in when it turns out the shot meant for Scully was the one loaded chamber. Mulder aims this at Modell and puts him in a coma.
Plot Hole: A minor one: Why didn't the FBI send Skinner to the hospital with the SWAT team? He already demonstrated his resistance to Pusher's mind control. But then, of course, we wouldn't have had that awesome showdown between Mulder and Pusher.
Sleep Cute: Scully falls asleep on Mulder's shoulder during a stakeout.
Small Name, Big Ego: Mulder and Scully think Pusher is "a small man", and that he welcomes the idea of going down as an epic killer.
The Sociopath: Modell has no regard for the feelings of others and perceives people as objects.
Suicide by Cop: Modell wants to go down as a big badass. Playing Russian roulette with Mulder definitely counts.
SWAT Team: They are used at the end of the episode during the climax in the hospital.
The Worf Effect: Double Subverted in Skinner's case: Skinner is the only one who wasn't influenced by Modell's compelling suggestions. However, we all get to know what Modell is up to when he gets Skinner beaten up anyway, and by petite Holly on top of that. In the final showdown, even though Mulder proved great force of will, at the end he couldn't actually resist him either. They would have lost if Scully hadn't pulled a fire alarm to break the spell of his voice.
Worthy Opponent: Modell was looking for one, and found exactly who he wanted in Mulder.
Wrong Genre Savvy: Agent Burst would be an excellent agent were he tracking an ordinary serial killer. Against Modell, however, he's clearly outmatched.