This is the bunker door when it's finished.
make a 6x2x3 hole in the ground, and on the far wall take out the bottom layer of blocks, and on the other side take out the two middle blocks one block up from the ground.
add sticky pistons to each side.
set up the redstone like in the picture.
completely fill in the floor at the level of the sticky pistons.
add pressure plates to the front side and there you have a bunker door