If he has a life for each of the eyes on his arm, all he had to do was take out the pein that ressuscitated the others and then take out each pein (or wait for nagato's chakra to end). And since apparently you can't find out where the "next" Danzo is going to come out from, I don't think it...
This is almost certainly true, since each time he used his power (whatever it is) one of the eyes closed itself. That's what Karin is watching.
It also makes Danzo a bigger bastard because he could have taken out Pein.
