If I walk around in the cold at night, will I get pneumonia? I read an article that said pneumonia is an old person's best friend due to it being a fairly gentle exit
Nah to both. I've had pneumonia and it's miserable. If you're not elderly, you will be miserable too. The fever is terrible, the piercing chest pains, the forceful coughs, the chills when you're not burning. I don't know why people say that about old people because it's still pretty nasty (guess there are worse things?); they do commonly get delirious, and they have weakened immune responses already - a lot of the nasty symptoms of pneumonia, like the coughing, are the body's attempts to make itself better by getting all that shit out of your lungs, and old people can't even do that properly. So they present with fewer symptoms and have less of a horrible struggle supposedly.
And pneumonia is caused by an infection in your respiratory system. You won't get it just from being cold.
Some post-WWII stuff I've read talks about how some people who probably wouldn't cope in a normal society seemed to function well in war. Not like actual documentary stuff, just novels from the time.