I wouldn't say it was so much smug then being relieved that once again his lies and nonsensical talk get him out of a jam and keep him living as he's done throughout the apocalypse. Don't think the drugging Negan thing was a thought at that point. But yea he is now up to something.

 

That smile threw me off too. I mainly think he's just doing what he needs to do to survive and not get other people he loves killed...and while he's at it he's sort of enjoying some of the perks. Then i remember that smile and I wonder if it was just a momentary thing or if he has some kind of scheme a-brewin'.

 

Eugene wanted some Saviors to get some more walkers for the yard. Eugene is then having molten metal poured on the walkers heads to make them hard to put down. I think part of Eugene's plan is to get as many of these metal head walkers as he can and eventually herd them into the Sanctuary and let them do their thing on the Saviors. Eugene might have other irons in the fire, but I can see this as one of his plans.

 

that's brIlliant!!!

 

Have to disagree. Someone relieved is going to give more or a sigh than a smirk like Eugene gave. I think he believes he passed the bullshit test and is now confident the Saviours aren't very smart.