It means just what it says. It implies that someone is telling you to do something now because in a short time you will no longer be able to do it.
For instance, as we grow older we are less able to do some physical activities so someone may say to you "you need to do a bungee jump while you can".
"with a weapon" is what "while armed" means
while
a while
You may mean 'temporarily' which is only for a short while.
it can mean masterbating with lotion while driving
See while you are sawin . . What does trough mean?
It mean love ya when texting
Like your blood is on your underwear while you have your period.
Every 4 hours while you are awake.
I had. And I am dumb.:)
Blogging while working
While or during