I guess Casket could Block or go Full Defense, but with his high Armor rating, it's probably not a big deal even if he gets hit; doubtful a ghoul could break through to infect him. For Defense Casket has: REA (6) + INT (3) = 9 dice.
Melee Defense:
9d6t5 1Ouch. Awful roll.
Assuming Casket needs to Soak somewhere in the 8P -1AP range. He has: BOD (4) + Globetrotter Jacket (12) + Ballistic Mask (2) - AP (1) = 17 dice.
Soak:
17d6t5 2. . . Well, let's Edge it.
Edge Re-roll:
15d6t5 5So, Casket takes something in the 0-3S range, most likely.
Casket is down to 1/3 Edge.
Well, my rolling today is not giving me a lot of hope for this, but by my count we've dropped 2 Ghouls, slowed 1, 1 is by Spikes, and another is by Casket, which leaves 1 Chilled ghoul and 1 yet uncommitted ghoul near the door. Assuming that Spikes is Prone, since she's Hot Sim, Chaim will use Suppressive Fire with his liberated Ares Alpha from the door to the ghoul standing over Spikes, which should easily fit in the 10m spread.
CT1 IP1
Free Action: Speak:
"Door, eight o'clock!"Complex: Suppressive Fire
The tricky part: Chaim doesn't have Automatics. He does have: AGI (5) + Edge (5) = 10 dice with exploding 6s.
Suppressive Fire Pre Edge:
10d6h5 4Perfectly average, but hopefully that's all we need. With the Ghouls being crazed and feral, GM discretion on whether or not they would have the semblance of mind to Hit the Dirt. Base damage is 11P -6AP. This attack should hit the Chilled Ghoul, the yet uncommitted Ghoul, and the Ghoul above Spikes.
Chaim is at 4/5 Edge, 22/42 Alpha
Now, we're back up to Casket for CT1 IP2
Casket will dramatically grab the Ghoul attacking him by the neck as he levels his short-barreled Defiance T-250 against the Ghoul's abdomen and lets loose with some more flechette.
Casket has: AGI (

+ Longarms (6) - Attacker in Melee Combat (3) = 11 dice.
Boom da Ghouls:
11d6t5 2Maybe somebody else needs to roll for Casket.
oh, I forgot Take Aim
Take Aim:
1d6t5 0Nope.
Ghoul takes a -3 modifier to its Defense test. Base damage is 11P + Hits.
Casket is at 1/3 Edge, 3/5 Defiance