Right now I'm assuming Merc 11 has enough sense to wait.
I mean, he's AI so he doesn't, but the enemy phase will come before he has a chance to do anything that would endanger Durnock. Last round from the same position Adele baited Archer 17 to his death. Merc 11 may clean out another Archer for us.
(XP/vulnerary vs. time optimization; in review, E7 is the better choice
Edit: oops, but Argoth is at E7. If Durnock wants prime real estate on next round's flanking maneuver he'll have to overextend into Archer 16's range.
Placed Durnock at F7 to conserve vulneraries [~potential damage from ballista cited below]. We should avoid much of the bottle-neck issue by starting the next round with having Oren shove Argoth into E8 and moving from there...)