Although BJJ is quickly and easily learned, i believe that guys who have good stand up skill, they will benefit more from this kind of practice than focus on ground work
The modification of this move is that your close arm should cover your face just like a boxer blocks a hook punch.
The other hand, which he palm plants against the wall is aimed at your opponents head or face and is a palm strike with weight behind it. If your opponent changes from pushing/driving you, that should be a hard enough strike to propel you whole body weight back into ballance.