Needle bearing pieces

Just pulled my needle bearing and am missing a small piece of it. The two bigger pieces were down inside the gap just on the inside of where the bearing sits. I have gone all over inside the diff with magnets, then blew air from different places while keeping magnets in it, then went around that channel with a pick and a magnet. Nothing. Doesn't seem to be on the floor either.

Is it possible that piece broke off previously and has been pulverized in the diff? Has anyone had a similar experience?

Edit to add- I did pack the diff with plastic and recovered everything I could before removing the plastic. Nothing should have gotten behind it

Thanks in advance

 

I'd just fill the diff and change it again in a few hundred miles.