User blog comment:San&Ashitaka/Chapter 51/@comment-124.195.216.68-20131108185539/@comment-24121336-20131109072125

Levi's old squad resembles his new squad, Eren knows that Armin, Jean, Mikasa and the rest of the squad will face the same fate one day just like Petra and the old squad did, being in the intense action.

I think Armins question was one we haven't taken into account, in the last few pages he said "Why were we picked when there are still more experienced [soldiers] than us"

I put in soldiers as the scanlation said warrior, which concerned me as that is what titan shifters refer to themselves as :S Must be translation mistake (I hope).