There's a hallway next to A/B/C/D security, just to the west of the information kiosk, that used to be accessible for this with no one there to give resistance. I don't think there's anything similar on the D/E/F/G side since xfer security is on the arrival floor on that side of the airport.

Access to the escalators appeared to still be there a few weeks ago walking past but its been years since I had any need to backtrack out of the departure floor toward immigration so I can't vouch it's still doable.