I took that scene to mean that law enforcement was now not caring about doing their job of serving and protecting the community, but instead thinking only of themselves.
I took that scene to mean the police already knew something wasn't right but decided to hide it from the community.
I'm wondering if they think the problem is a Los Angeles problem, not a worldwide problem. So they are leaving problematic L.A. and everywhere else will have full supermarkets and safety...so need to stock up on anything.
Tobias told Maddi that he read stuff on the internet so it clearly wasn't just an LA problem. If she gave Tobias back his knief, it probably should mean she believed what he said right? And then they saw a walker together...