His PM talks about transformation that can't be halted, and there's also a part of his role PM that is redacted. I kinda assume that if something in your role PM gets redacted upon flip, that clues you in on the fact that something suspicious is about to go down with you. If you also add the bit of flavor knowledge where those machines are fought - which in all fairness idk if Polar had that knowledge - then I for one upon seeing that role PM would follow, alright I'm town for now but probably not forever. If you know you're ultimately gonna be scum, you play scum from the start, you can't fool yourself by thinking but herp derp it says I'm town right now so I can just play town.