The enemy advances over a crest and then crosses open ground with little protection before reaching close range. A route through lower ground or a gap in the terrain would keep the troops covered for longer. The shortest path to the defender is therefore the more dangerous one. Terrain has already shaped the engagement before the main firing begins.
Notable Point · 30:13-30:46
Using terrain to cover an infantry advance
A direct advance over a hill leaves troops exposed, while a route through lower or broken ground would keep them under cover for longer.