Still composure, and the appropriate course of action is still to evaluate your options and choose the best one, even if that's the best option out of a list of bad options.

Unless you think that panic will induce the driver to stop accelerating, I suppose. Though I think the closer analogy would be "you're a passenger in a car with a brick on the accelerator and no driver", because I don't think there's any person or coherent group of people who actually control the global economy (in the sense of "control" where they can make sweeping changes that go against local incentive gradients, and have those changes stick).

If doom is certain, then what does your composure or anything else matter?

If nothing matters, in what sense is panic the "correct" response?

Also, it's useful to check whether you're absolutely doomed to lose everything you value, or only probably doomed to lose most of the things that you value, in situations where you appear to be doomed.

I don't think a panic response is generally helpful towards the goal of "make the best you can of a bad situation".

your chances of survival increase if you're not panicking.

This is well understood by everyone and only needs to be said because you feel the need to ask 20 questions in an attempt to imply there's a fault to the thinking (because you can't outright say it or the jig would be up).