Love the idea of choosing between scanning people and trusting them! I think it would be cool to have a safe zone for survivors right there in the level. You’d have to choose between taking the time to scan someone or just hoping for the best. Any infected survivors who slipped through would reveal themselves once they reached the others. So you have to go back and make some deals with it instead of rescuing others or just defending yourself.
The level could end when the player wraps up the evacuation as far as the player reaches the minimal threshold. Good job!