I’m not that expert in AE, so your question is beyond me too.
However, I would probably never have the wall go to 100% see-through (0% opacity). I would let it hover around 5% (or whatever looks good) so that the texture you apply to the wall to make it look 3D never goes away.
If you want to remove the wall 100%, and have some texture around the hole, you could use “bevel” (but this would require that: 1) you do your initial effect; 2) you hide the layer with the wall; 3) replace that layer with an identical layer with a hole pre-cut in it, and apply the bevel to that.)
To be honest, I don’t think it’s necessary since we’re seeing through a wall magically, and not actually putting a hole through the wall.
Sorry for the late response.