If Gumbo would have kept his head behind that duracrete pylon, nobody would have gotten even a shot at him, but unfortunately for him he kept pecking out a few times to shoot himself and thus shooting him was harder than without the cover, but still just needed to penetrate that armor. Besides Laminate Armor gives zero defense anyway. So you get one defense from the smugglers coat, you get the hidden pockets and irrc soak stacks if it is not from the same source.
If that's what Gumbo's PC says he's doing, sure. Anyway, we're not going to solve it here. At the table, I solve it case by case with what makes sense.
And you are recalling correctly, sources of soak do stack! (unless they are the same source, Eote Core pg 207)
