En Ami

Mulder:  You said she was, uh, carrying a suitcase.  Did you notice anything else, anything abnormal? Landlord:  No.  No, actually it wasn't her carrying the suitcase.  It was her driver. Mulder:  Her driver? Landlord:  Yeah, older guy... tall.  I've seen him here before.  Smokes like a chimney. [Mulder stares at the landlord, then turns and leaves the hall just as the landlord gets Scully's door open.] Landlord:  Hey, don't you want... [Mulder is gone.]

Well that's typical.  Just as he's getting what he wants he up and leaves.  You would think that he'd warn the landlord before just taking off.  But no!  That would take too much consideration on Mulder's part.

General Punkesque Behavior

Mulder has no manners!  After getting the super to let him into Scully's apartment he then walks away before actually gaining entry without saying "boo" to the landlord.

You can just hear the "I told you so" in Mulder's voice when he told Scully that she'd been used.  What did he expect Scully to do? She had to try to get that disk somehow.  Did he think that she wasn't willing to go as far as possible to get to the truth?  Or is it that he thinks that he's the only one who's willing to sacrifice himself to get to the truth?

Unprofessional Behavior

Bursting into Skinner's office:  I suppose a phone call or a knock on the door was too much to ask for.  That's really going to endear Mulder to Skinner.  Not!