Shower Door

So, our shower is in a very small and poorly ventilated bathroom.  It is also sort of like a glass booth.  As such, every time I shower, I make sure to leave the shower door open so that all the moisture can dry faster, therby discouraging mildew, mold, and what have you from forming.  Stan has never left the door open.  Ever.  

Stan: "I'm going to shower now."
Me: "Ok, as long as you mean it this time."
Stan: "What?"
Me: "Last time you showered at night, you said you were going to shower between 9 and 930, and you showered at 1030, when I wanted and normally shower."
Stan: "Sorry."
Me: "Make sure to leave the shower door open from now on, though."
Stan: "What?"
Me: "....You know why, right?"
Stan: *With attitude* "So that nothing grows..."
Me: "Right."
Stan: "Well, I always leave the door open."
Me: "....No.  No, you don't.  You always leave the door closed."
Stan: *long pause* "That must be the door slamming whenever I leave for work in the morning!"
Me: "..."
Stan: "There's always the sound of a door slamming whenever I shut the outside door.  That must be it.  I always leave the shower door open."
Me: "....Well, whatever, but it's always closed whenever I come home....and you're the only other person living here."
Stan: "No, I always leave the door open. *leaves*"

Well...no...even when he showers at night, he leaves the door closed.  I know because I shower later and the room is moist...and the door is shut.

Also, it's been 15 mins, and he still hasn't gone to shower.

*Edit*

So, Stan walked by 20 mins after he said he was going to shower and he was "on the phone."  Dunno if he just did that "look I'm important" thing again, but in any case, I needed to use the bathroom and I didn't want to wait in case he stayed on the phone for a long time.  So I grabbed my shower stuff and went.  As I'm using the bathroom:

Stan: "Um.  In case you didn't notice my stuff is in the shower."
Me: "....Ok..."
Stan: "Yeah."
Me: "It's been over 20 mins."
Stan: "Well, 20 mins ago, I said I was going to be in the shower within 15 minutes."
*Silence except for me USING THE BATHROOM*
Stan: "....So, that's still within margin of error."
Me: *Thinking* "Stan, this is not Orgo where the professor took pity on you and bumped your grade up: 33% is not a good number and is definitely not a B-."
Me: "Ok."
Silence as I'm now washing my hands and not coming out.
Stan: "What're you going to do with my stuff?"
Me: "...Put it on the sink."
Stan: "Ok, thanks."
*Sound of angry footsteps*
Me: *loudly* "Try to be more reliable, Stan!"

If I actually could trust him, I wouldn't have cared that he was 5 mins late.  But, he's proven time and time again that I just can't trust him.

*End Edit*