...Oh. I did not think that through.
Gell notes the southern group is already pretty well finished, and moves to help Zalgrin finish the northern group.
SpoilerMove action: 20 feet north, 20 feet northwest (ending at F-19)
Free action: Create airblade arrow
Nonaction: Spot check vesus gnoll at C-25
(1d20+17)[33]
Standard action: Attack gnoll C-25
Attack roll: (1d20+19)[21]
Damage roll: (1d4+4)[8]
Skirmish: (2d6)[7]