Overrun Position

One of the usual Covenant tactics to neutralize UNSC firebases is to drop in troops over or perilously near the trenched marine position. Either the assault group makes the humans retreat or causes heavy losses to them before being wiped out.

The tactic, which could at first look suicide, become more and more prevalent as UNSC Marines numbers decreased...

UNSC Marines try to take back their outpost after Covenant troops overran it. Human forces quickly learned to retreat and reassault in this kinds of situations, even setting traps and explosives as "surprises" for the invaders.