Is it possible to obtain a SSS ranking on (Extra) Mission 54 - A Warrior's Soul?

[FRMadCow56]

While hunting for missing materials, I've been replaying all the missions at each difficulty until I can earn a SSS ranking. I've almost got them all except for the 4 missions in Chapter 9 on Ecstasy difficulty (just can't avoid being hit at least once...sigh) and mission 54 in the Extra section (on any difficulty).

Taking no damage and completion time is not a problem (get S ranks for both), but I consistently get a kill score of 2970 which is always an A ranking. I thought I was just missing a spawner that maybe I was killing too fast before I let it spawn some enemies (like a gold pile or one of those skeletal mage looking guys), but there's nothing like that in this mission that I can find.

Anyone else who has played Extra mission 54 have any success in getting a SSS ranking? I know it's not tied to any achievements or any unlockables (getting SSS ranking on every mission on every difficulty), but it's just been a goal of mine while trying to obtain the materials I'm missing. I might just end up skipping it if it's glitched.

[FRMadCow56]

Well, I finally got SSS rankings on all the missions except for this one extra mission (on any difficulty). Best I keep doing is a S rank because my kill score just can't get high enough.

I tried searching for tips and I think it's been said that the orcs with rocket launchers can spawn additional enemies, but I've never seen them do it. Though it hardly matters since no matter who my buddy is and how much I try to gimp their damage output at this point (all my characters are at level 99), they kill them pretty much instantly when they get too close.

I have one last dialogue event to unlock (it's between "Dragon's Blessing" and "The Princess' Favorite") and since I think I've done everything else, I'm guessing SSS ranks on every mission unlocks this. Not a huge deal I guess, but it's a little frustrating since I'm so close.

Definitely if anyone has any tips on how to SSS rank (Extra) Mission 54 - A Warrior's Soul, I'd love to hear it.

EDIT:

Wow, I'm blind; never saw the button for removing the buddy at the select screen. Going solo for this mission seems the way to go since now I was able to spare the orc with the rocket launcher a quick death and he does indeed summon more orcs (which is absolutely necessary to get a S rank in kills on this mission).