Problem-solving Styles in Strong Willed Children

In the shower, with three of our kids home and my bedroom door locked, I get exactly 13 separate knocks on my door. All three kids need to get into my bedroom/bathroom... not in ten or fifteen minutes, but NOW.

This has caused me to reflect on the various tactics and strategies each of our kids uses to get his/her way. 

MK: "I just need to come in to get one thing. And I'm soooo late. And I won't be back home til the middle of the night, then leaving for the airport at 6:00 a.m. So you can see how my emergency is now your emergency...."

Mia: [BANG BANG BANG on the door]: "MOM!! OPEN THE DOOR!" 

"Is this an emergency?" 

"HURRY!! OPEN THE DOOR!!" I go dripping wet with a towel around me to the door and open it, she blows past me and grabs a ponytail holder.

Getty: Makes an unbelievably loud commotion in the hallway on the other side of my shower wall to make me think he's met with some unfortunate accident. I come running out my door to find him laughing—so delighted, in fact, that he's forgotten what he needed in my bathroom in the first place.

Cy: Stands at the door and says, "Mom!" 347 times until my shower is over. 
And they say persistence is a virtue.

Cam: I say, "I'm in the shower. I'll help you when I get out." Tears fill his eyes, he hangs his head and sulks off to find a blanket to put over his head and wait until I get out.

Elle: Screams in her highest pitch and then threatens, "Mom! I need to go pee—only in your toilet!" And then, if I wait too long to respond, she'll leave a puddle just outside my door. (She could pee on demand.) 

 
I'm strong-willed myself, so I've considered running away, putting myself up for adoption, banging my head against a wall—all viable options, but I figure it's safer to be accessible ... though my sanity is at risk.