Friendly fire

[60]

I know that you will lose trust when you set other survivors on fire/blow them up. But does it hurt them? Can i accidently kill them?

[WillieSea]

No, you cannot kill them. And they only loose trust if they are not your friend. But it will 'hurt' them so they need to heal. Hopefully, you have a doctor back at base.

Only zombies can kill them.

So, if someone is about to be killed by zombies, toss a firebomb or other explosive into the pile to save them. Or run the whole lot over with a vehicle. The survivor will survive, and the zombies will likely all be killed.

[Magic Mark]

You can kill them by spamming the grenade launcher at them, according to somebody else's experience, but I haven't seen it done myself.