natcin

^ yea thats what i thought was probably the case as i was writing that as well, but the staff i spoke to didn't even flinch or hesitate when i said i wanted to exit airside. so perhaps there might be some pathway that leads downstairs to where the arrival immigration is.

this is considering that the shuttle leads back to the bottom level of the main part of 2E where you mentioned that the P lounge is any way, so wouldn't be surprised if there is a one-way elevator or stairs leading back down to arrivals immigration.

i was already airside. my exact path was this:

checked in, got boarding pass
headed to international passport control to have my passport stamped to 'leave' schengen
took the shuttle to security check point
went through security check point (that was when i realized i lost my phone, but i went through with security anyway as i didn't want to hold up the line at the back searching through my bags)
after i passed security, i searched through my bags and confirmed that i had lost it
at this point (I'm standing in front of all the duty free shops) i was looking for a way back into land-side and the staff walked past me and thats when she pointed to a small gateway right next to the very security check area where i had passed through

hope that helps visualize the path! so the only thing left for me to do really was head to the boarding gate and board my plane. this was on a CDG-PVG AF flight