I have some suggestions, if you don't mind
You could add a mode where it isn't apparent who is infected, and it doesn't announce who patient zero is. I think it'd be an interesting mechanic, kind of like TTT.
I feel like too much of the game is "all the infected are dead. wait for everybody to get into the heli." Is there really a point to this? I think if all the infected are dead, it should either restart or spawn infected bots to get afkers/slowpokes.