Gravity question?

if you fired exactly straight in the air the bullet couldn't have enough speed to escape earth's gravity. When it cam back down it would fall at a terminal velocity. This means it would go up in the air, stop, then fall and speed up until the force of gravity was canceled out by air resistance. They did it on mythbusters and it wasn't fast enough to kill someone. However, if you shot the bullet at a slight angle it would travel a great distance and maintain it's horizontal velocity making it deadly. There are doented cases of this happening and killing people.