Anyone who's watched The Walking Dead knows that Merle is not an easygoing guy, even if he has seemed like it during his time in Woodbury. When the Governor told him no after he requested to go looking for his missing brother Daryl, Merle didn't seem to take it particularly well.
But clearly he feels indebted to the Governor and, knowing the man's true colors, is probably a little scared of what might happen if he disobeys. So...what's his next move?
Well, I think the answer might be hidden in another scene from last night''s action-packed episode, in which the Governor seemed to tell Andrea that he was going to allow Merle to look for Daryl. It seems likely that, sooner than later, the pair (who seemed pretty at ease with each other this week, in spite of Merle's crass attempts at relating to her) will be talking and Andrea will realize that The Governor is telling her a different story than he's telling Merle. It seems likely Andrea won't be pleased.
A partnership or alliance between the two could be pretty fertile ground to explore, story-wise. Seeing his most trusted aide and the girl he has a crush on becoming close could knock the Governor back on his heels a bit, putting him at a strategic disadvantage if the pair have to square off against him--but it would also likely be seen as a personal affront and something that he feels compelled to respond to.
Where such a triangle could go is anyone's guess, really; certainly neither Merle nor the Governor are particularly easy to predict, and Andrea is so much different from her comic book counterpart as to make her almost as inscrutable. In fact, if there's any longtime survivor that's likely to die an unexpectedly early death, my money would be on her. It could be a hugely motivating factor for both Merle and Michonne, either separately or together.
The other option, of course, is almost the exact opposite. In the comics, the Governor was eventually "assassinated" by one of his own subjects, who suddenly realizes the Governor is a maniac as the scales fall from her eyes, too late to prevent her from killing Lori and Judith (the baby, just born on the show, who apparently won't be squished to death by her falling momma in the show). It wouldn't be too hard to imagine the Governor and Andrea continuing to grow closer together, until she finally realized--either through Merle or in some other, more traumatic way--what kind of man he was and decided to put a stop to him herself.
The fact that Andrea hasn't yet become the combat force she is in the comics could go either way for her in this scenario; taking on the Governor could prove her mettle and put her in a whole new mindset, or her lack of skills and experience could prove her undoing, putting her in a great position to be an unexpected fatality in a big episode. It's very difficult to tell which is more likely.
Merle has similar issues, but his destiny is even more unpredictable because there is no comic book analogue for the character. There's no expectations built in, no sense of direction for where the character might go. The smart money is on he and Daryl reconnecting at some point, but whether Merle will have turned against the Governor by then is anybody's guess. If not, will he take after Daryl and the group?
Interviews done before the season began seem to suggest that Merle would be the same kind of dangerous wild card here that he was in the first season--but so far, he seems to place all of the blame for his lot in life squarely on Rick's shoulders. Would he even care about getting "revenge" on anyone else in the group? Who knows. It's hard to even guess whether this new, more mellow Merle would actually take after Rick if it becomes clear to him that Rick has helped to keep Daryl and the rest of the group alive, even at a cost to him of his wife and best friend.
In any event, Merle certainly seems to be in a spot, and it doesn't seem likely that he'll be comfortable under the Governor's thumb for much longer. The real question becomes whether his loyalty to the Governor and to Woodbury will outweigh the feelings of resentment he seems to have.
If I had to make one guess, it would be this: Come time for The Governor to die, Merle is still alive. Remember all those fans who suspected Merle might actually BE The Governor a while back? What if, with "Philip" shuffling off this mortal coil, he actually turned out to be the man's successor?