Its not just staying alert.
Its situational awareness, let it radiate out around you.
This allows one to be relaxed, completely aware, and ready to act.
Just alert imp;lies being all cranked up, Nit a good way. You burn out.
But cool awareness is good, Keep your weapons close, well maintained.If you are lucky , you will never have to use them.
Cooper’s colors: A simple system for situational awareness
Its not just staying alert.
Crouching Tiger, flat footed , is what my Marine brother calls it.