[TalonDJ]

The armed guy couldn't simply say to the other guy, 'Hey, can you take the controls whilst I lock up my pistol?'

Most airliners also have map lights in the cockpit so the pilots can read their maps at night.

Those lights are not all that bright.
There is still stuff going on in the cockpit to distract him even if his hands are not on the controls.

You should never handle a gun if there is not a 'safe direction' you can point it in, regardless of lighting and distractions. In the cockpit of an aircraft there is no safe direction.

[Ol' Dan Tucker]

Those lights are not all that bright. There is still stuff going on in the cockpit to distract him even if his hands are not on the controls.

They're bright enough to read maps.

There's also another guy to handle the airplane while he's fooling around with his pistol.

In the cockpit of an aircraft there is no safe direction.

Sure there is. You can always point it to the side of the airplane, under the side cockpit windows. There's no vital electronics or cables. One little hole won't cause the airplane to crash or depressurize.