In a room full of panic, the calm person becomes the plan.

Panic is contagious and so is calm, and in a loud room the slower person becomes the center by default. Calm is not the absence of fear, which nobody has. It is being one beat later to react, long enough to say something specific while everyone else is saying everything at once.

In the next chaotic moment, lower your voice rather than raise it and ask one concrete question. Who is hurt, what do you need, what happens first. And if you are the one panicking, that is not a character flaw, it is a normal nervous system doing its job loudly.