If the plane is flying at high altitude the
pressure on the inside of the plane is higher than the outside of the plane.
This is
because the plane is pressurised so that the pressure stays the same as it would at ground
level (roughly 100 000 Pa).
At, say, 10 000 m the air pressure outside the plane is much
lower (about 30 000 Pa), roughly one third of what it is at sea level.
So if the door is
opened the higher air pressure in the plane will blow you, and everything else that is not
fixed, out of the plane.
So you actually PUSHED OUT not SUCKED
OUT!
Not a nice thought.
Of course eventually tthe pressure in the plane will fall to the same as the pressure outside it.