Microscopic idea of sudden extreme pressure difference I'm having some issues understanding what's happening microscopic when there's sudden changes in the pressure. 
The microscopic idea, is that particles randomly bounces around each other. It's even possible with entropy to state all the air can go to one side of the room, and leave a vacuum on the other side but off course very improbable. 
But if particles just randomly just bounces around, why are you being sucked out of a space station, if the doors are suddenly opened into the vacuum? Why can the molecules around you feel the doors has been opened another place, if they just randomly bounces around? 
 A: less pressure means there are fewer particles in a given volume (assuming constant temperature). This means that as you create a pressure differential, particles at a place of higher pressure have fewer particles to bounce off against, thus they move towards the volume with lower pressure. I hope you can see how this discrete step of a flux of particles between 2 volumes will procreate within the volume we're talking about, thus creating a suction force due to the flow of particles. 
so basic, there are fewer particles to bounce off in the direction of lower pressure, thus creating flow :) 
A: They are still just "randomly" bouncing around.  The problem is that you've now changed the constraints for which they can randomly bounce.
Before, the odds that they could randomly bounce outside the ship are extremely limited.  For the most part, bouncing is constrained to other particles and the walls of the ship itself.  As soon as you introduce an easier pathway out of the ship, some of the gas will begin randomly bouncing out that hole.  What's especially important is that once they start to move away, it's extremely unlikely that much of the air escaping will bounce back into the ship.  Instead, they are free to start permeating space where they have very low chances of collisions that would send them back.  This creates a net flow rate out of the hole compared to the essentially evenly distributed bouncing around when it is enclosed by walls and pressurized gases.  
If you're facing the hole, collisions with gasses behind you are likely to send the air essentially backwards, hitting the air behind it, which cascades until it hits the wall and essentially pushes back on you.  In front of you, when you push against the air, it collides with more air, which cascades; but there is no wall to push back against it, so the air just starts flowing out the hole.  
The best analogy I can think of is to consider the air somewhat like a spring.  Imagine you are a mass between two springs that are compressed between you and a wall on either side.  There are forces acting on you, transferred through the spring to the wall; but they act on both sides and are balanced.  As soon as you remove one wall; three is no longer anything for one spring to compress against, so the other spring which is still compressed will begin to push your mass and the other spring towards the location where the wall used to be.
