No genuinely explain, why would Loki end up chained to Yggdrasil if he and shanks figured out a plot? You get how actually dumb that is right?
That IF Shanks and Loki had discussed the thing, Shanks wouldn't have had to chain Loki.
But Oda doesn't write smart characters. So, instead of Shanks explaining shit to Loki and the two of them planning a future joint assault on MJ, Shanks tricked Loki so that Loki could badmouth his idolo in front of Luffy and we, as readers, could be shocked by it because, oh my God, Shanks is so mysterious in his ways, I wonder why he's doing all this?! Like it's isn't fucking obvious to anybody with half a brain (or a quarter, in your case) that Shanks is acting for tHe GrEaTeR gOoD.

