I go not the random way.
Exploding heads are only possible with the right hard weapon,like the sniper - and - if the player is in the correct range to the zombie. So the splatter on the wall is only possible, if the zombie is in a short range to a wall and the bullet is fast enough to pass through the head. The splatter on the view is also only possible in direct range to the enemy. Sure, I only make phantasie calculations with variables, which I think, they could be correct.

The only action, the player will see everytime is much much blood