You could just remove the 'beam' of the laser so no one knows where the mine is/if there is a mine. Or make it very very subtle so it's hard to see if you don't watch out. Or make it a very short beam but the actual trigger is a lot 'longer'.
We'll see about the AI turrets.
Opening sealed doors (sealed by shooting the controls for example) is a good idea, but we need those doors first, although they shouldn't be too hard to do.