Thornwhip succeeds. Knight uses the opening to disengage and flee.
Levinshire targets Caer with a Chill Touch but I crit-failed. He then retreats. Although, you could still hit him with a ranged weapon. he has 3/4 cover.
Zombie attacks Havoc:
zombie attacks: 1D20+3 = [20]+3 = 23
1D8+1 = [7]+1 = 8
Zombie attacks Deidre
1D20+3 = [10]+3 = 13
1D8+1 = [7]+1 = 8 damage
Zombie attacks Stratus
1D20+3 = [17]+3 = 20
1D8+1 = [5]+1 = 6 damage
If you move in now, you will be safe but 4 stragglers left outside the gate will die. (Assuming the zombies hit. They could, actually miss) I've marked them with red dots.
If you hold off the zombies for one round, you can let the 4 people through. Basically, you will have to hold off another attack for one more round. Unless you have another way to help them.
Reminder: please keep a mini-sheet at the top of your post. Although, without it, I have no idea what your HP is so I'm not tempted to pull punches if you're close to dropping. So that's a bright side....I guess...