Eventually you can move into the 2nd spot..
Exactly, focused on one with somebody coming up behind you...
Ain't combat great?
That's actually where a spotter will come in handy, it's like having a wing man on the ground. You'll need to practice though. I've sat there and watched things come up and go by before I could get my silly mouth to say something other then 'uhhhhh, that was cool'.