Having your eyelid cut down by the scope is one thing, having a donut sized hole in your forehead from the scope, with or without the cover is another!
No reason to remove the scope cover when you have it pressed against another ones forehead. Even if the bullet would somehow miss, the blast would take his head off!
Never bring a knife to a gunfight and if you have a choice of what to bring to a gunfight make sure that it is a friend. If you have a choice of weapons always take a long gun.
Should you ever die by your own gun, it should be by clubbing, because your out of ammo.
Long distance the next best thing to being there! No need to run, you'll only die tired and out of breath.
"When in doubt shoot again"