HB: Isn't Called Shot -4?
Init:
3d6+10 23Not sure on the force of the Earth Elementals since they're 2d6 + Fx2 - 1 normally but you rolled 3d6+10. I'll guess that's astral init, which would make them F5.
So when Marcus described the patrols they were close to the dome, but the van's now driven a quarter mile from the first encounter, so she's around 500 meters away now, which makes it long or extreme range, depending on which side of the 500 it falls.

Since she's same init as Marcus, unless someone else ends up going first, she wont know it's shooting time till he goes off, so pass one is Take Aim twice on the elemental furthest from him. Pass two will be Take Aim again, then Called Shot Vitals (Elemental's got nards!), then Single Shot.
Long/Extreme Range w/Scope: -1/3
Shoot the Elemental!:
13d6t5 5If you decide it's Extreme Range, I'll reroll misses with Edge
Edge Re-roll:
8d6t5 1For all the good it does.

Long Range: 5 Hits, Extreme Range: 4 Hits
Assuming this would be a surprise attack since the Elemental should be looking at the van or Marcus.
Gun is 12P +2 DV from Take Aim + 2 DV from Called Shot, -1 AP with APDS for a total of -5 AP.
Long Range: 21P -5 AP
Extreme Range: 20P -5AP
F5 Elemental has 10 Hardened Armor, so a resist pool of 10 with 5 auto-successes (countered by the -5 AP), so should just be a pool of 10.F5 Elemental has 10 Hardened Armor, so a resist pool of 10 with 5 auto-successes. -5 AP means a pool of 5 and 5 auto successes.
F5 Elemental has 9 Body, so 13 Physical Boxes. It needs 8 successes out of 10 to survive the Extreme Range shot assuming I did all my math right.F5 Elemental has 9 Body, so 13 Physical Boxes. It needs 3 successes out of 5 to survive the Extreme Range shot assuming I did all my math right.
Init pass 3 will be to shoot at whatever looks shootable, so Take Aim to reduce range, then single shot.
Shoot the next shootable thing!:
17d6t5 6 (4 if Extreme Range)
12P + 6 (4) - Opponents Defense Roll, AP -5
I'll IC once I know what happens.
