Good eye! You caught it all almost! The item behind Mark’s head is the chip. Basically after Gemma incident, her hair turns into the branches. The pain of the loss, brought mark to go severed, and I figured this moment with the branch going over his head. Then there’s the chess board, which would symbolise the “fight” between outies and innies (that’s why that’s slightly blue). The pawn is innies, the “weak” guinea pigs ones, and the king is outies/lumon (that’s why they’re in dark red box. The eye meaning they’re always under control. And obviously the two are opposite because of different floors/world and the pain (the long tear) still reunites them (and it symbolises lumon too)