It's not that hard, you just need to remember that, for every ability or way you want your zombie to react, you need to break it down and set them up 1 by 1.
So for your example, if you want the zombie to only break the walls for he is chasing the player, use a variable to determine which mode the zombie is in, than set the events in them.
If zombie is chasing player, set variable1 to 1. Than, while variable1 is 1, and zombie on collision with player made wall, wall destroy. You can set it to play any animations at that period too if you want.
Remember that every action you want your zombie to perform, you need to individually define them.