does anyone tried to use 4 Scatter Shot in the last boss of 50-55 MD?

[ZENSEKI]

I watch a video,an archer use lv2-3 Scatter Shot(?to deduct the boss' rage?) 4 times in the last boss fight, and the boss doesn't duplicate itself till he was dead.
the remaining players are 2 knights using slash and shadow thrasher all the time
and 1 mage using healing skills and pur.

[ZENSEKI]

lol, i watch again and know the answer now

[skatsteyp]

Scatter ShotEdit
Cooldown: 15 seconds
Rage Consumption: 30
Level 1
Prerequisites: Commander Level 22, Level 1 Battle Prowess
Description: Debuffs one positive buffs for all enemies
Level 2
Prerequisites: Commander Level 40, Level 2 Battle Prowess
Description: Debuffs two positive buffs for all enemies
QTE: Rage decreases by 10
Level 3 (Max)Edit
Prerequisites: Commander Level 50
Description: Debuffs three positive buffs for all enemies
QTE: Rage decreases by 10

it was use to debuff, not to deduct rage. maybe they we're using scatter shot because boss in level 50 md using guardian and dmg increase (correct me if im wrong), but back then when im playing that mp we have a way killing that boss before it summons its replicates
first : must have archer with df
second : must have another archer with level 3 delphic(also with descent patk)
third : 1st archer must use df when boss reach its remaining 1½
fourth : 2nd arches must use delphic when 1st archer hit the boss with df
fifth : pray for delphic to crit