Really cool idea, I hope this works well. I will try it out tonight.
This plugin sets `director_no_human_zombies` which controls whether players can be special infected. What happens if no human zombies happens to be enabled when it's time for an infected to spawn? Could a survivor grief the infected team by spamming this? You may want to have some sort of per map limit on this.
Also you may want to change this message to be more meaningful, I don't know if players will understand what being 'away' means and they probably won't want to go there.
PrintToChat(client, "\x04[SM]\x03 Type !away to go away");