Passengers need to understand before getting out of their seats that the aircraft is designed to fly safely based on annunciations of critical faults to a crew trained to address them.Part of the CRM process also includes the cabin crew who can contact the cockpit via phone etc.
Passengers can notify the cabin crew of their concerns but should not become the more serious problem by disobeying orders to sit down.
So as passengers you can scream yell and wave your arms to attract attention, but realize that the cockpit crew has got to fly the aircraft by virtue of the warning lights and displays in the cockpit designed for the purpose.