Oh my god, I have just realised. They would need to guard Baymax against both internal and external threats. Because, c'mon, if you were in one of the other troops of people floating around, and you realised that this troop had a Baymax, you would absolutely want to steal him for yourself. He has to increase your survival odds significantly. So this troop is not only trying to avoid zombies, but they also end up mistrusting every single other human being they meet. The humans would be living in a state of constant paranoid fear, and Baymax would just be like "Your adrenaline levels are elevated and you appear to be worried and unhappy. Diagnosis: stress. I recommend a hug"

The dytopia becomes even more dystopian! But with more hugs!