Spoilers ahead for those who have yet to watch tonight's episode of The Walking Dead.
Tonight's episode of The Walking Dead, titled "Sing Me a Song," affixed a lot of attention to Negan and Carl in the most uncomfortable buddy cop comedy ever, which means viewers got to spend more time within The Sanctuary's walls. Which means viewers got to see (and hear) Daryl once more, and this time, the guilt-swamped redneck finally got some good news, in a way, via a note from a secret sender. The answer to who delivered it seems really obvious, but is it?
Just to lay down the facts, after Negan announced to Daryl that he was bringing Carl back home, Daryl spouted out a general threat, which landed him back in his solitary confinement. (Otherwise, he was living it up outside...fenced in under the hot sun.) But the light beneath his cell door was briefly blocked by an unknown ally, who slipped a note through that said "Go Now." On the back of that note? A key. (It would have been nice to hear Daryl say, "Holy shit," here.) But who gave him the note?
The obvious choice would be Dwight, who has been seen to not-so-vaguely idolize Daryl with the usurping of his duds and equipment. Dixon cosplay doesn't necessarily mean Dwight wants to play hero, but he had just delivered Daryl to the cell, and he obviously had the quickest access to the door's key. The comics tell a story of Dwight finding redemption in a way - though without the non-comic Daryl involved, which throws a wrench into things - but we watched him play a big part in treating Daryl like shit already. So maybe he isn't exactly the person looking to cross Negan.
It might just be someone who shares Dwight's initial distaste for Negan's ways, with the same amount of reasons for wanting to go against the perverse leader's will. Someone that Dwight is pretty close to, who would have access to him having access to that cell's key. Of course, I'm referring to Sherry. After all, she'd already tried to escape Negan's death grip on his Saviors, only to have her sister die, followed by Dwight suffering for it with an iron to the face. Later, her efforts to spare Mark's face for his diddlings with Amber were rejected by Negan, giving her further anguish when Mark's skin sizzled. And she shared a smoke with Dwight, which is prime key-switching time.
But just because there are two choices standing out in a sea of unfamiliars, that doesn't mean it has to be one of the pair. Daryl is no doubt bouncing the "Fool me once..." idiom around in his head, since he has already been down a road where it looked like escape was his for the taking. That ended up just being a big "Gotcha!" by Negan meant to further fuck with Daryl's mind and build up his less-than-subordinate headspace. Fiction usually doesn't cry wolf twice in a row like that, but the note could damned well be another debilitating prank from Negan coinciding with his absence from The Sanctuary. Maybe it's a test for Dwight's emergency preparation skills.
Final theory, which links up with the one above: Daryl is getting messed with, but it's Dwight doing the messing and not Negan. Maybe Dwight has seen enough of Negan's actions, but without a clear exit route for himself, he chooses to take that anger and start playing his own games with Daryl. Nobody inside The Sanctuary is mentally at 100%, and Dwight has been shown to be as far beyond moral as anyone beyond Negan, so I wouldn't be surprised if he's capable of going all Jigsaw Killer on Daryl as a side project.