Get things done one by one.
What is the best way to deal with chaotic situation? Do one thing at a time, no matter how messy the situation is.
Things will get worse if you get panicked. You might want to look for a silver bullet, and would be devastated more as you notice that there’s no magic bullet.
The only way to remedy the situation is to surrender. Embrace the current situation and do one thing you can do right now. And repeat. If you work as a team, everyone in your team has to follow this protocol.
Be cool even when you face something in chaos. We all have the power to control it.