Well, he certainly seemed surprised and confused on where she was when she went missing and needed Daryl to explain things to him. And also a bit unsure of himself when "coming out" to the rest of The Group when it came to telling them about The Governor's plan and saying how he almost went through with it when talking to Herschel and the rest of the group about now not being sure where she was.
Further when Michonne and Meryl talk in the car Michonne quickly figures out that Merle is doing this own and Merle himself conforms this saying he did it to hopefully save his brother because he didn't trust Rick to do this.
Merle uses a ruse to take Michonne out of the prison and then there's this from the Wikipedia Recap of the episode:
Rick is scavenging wire to tie up Michonne, intercut with Hershel praying with his daughters, when Rick hallucinates in the sunlight; Rick then abandons the task and his intentions to hand over Michonne. However, Merle has already decided to do the group's dirty work, recognizing this as his role as it was in Woodbury, and he blindsides Michonne. When Merle and Michonne are discovered missing, Daryl begins tracking them on foot.
....
Rick convenes a meeting and tells the group about The Governor's offer, confessing that he was going to go through with it but changed his mind, but Merle took Michonne on his own, and Daryl went to stop him. Rick admits it was wrong to not tell them and apologizes, stating it wasn't his call to make alone. He says the group is the greater good, collectively the reason they're still alive, and he won't be their Governor.
If Wikipedia isn't good enough from you, from AMC's own
recap of the episode:
Outside, Rick finds a cable to bind Michonne. Lori appears on the catwalk. "You're not there," he mutters, cradling his head. When he looks up, Lori is still there. He throws the cable away and leaves.
Hershel, Maggie and Beth are praying in the cell block when Rick enters. He pulls Hershel aside and declares the deal is off.
Meanwhile, Merle takes Michonne to the tombs under the pretense of clearing out walkers. He then knocks her unconscious, drags her to the boiler room and binds her wrists.
Later, Merle walks Michonne down an abandoned road and explains the Governor's proposition. He says Rick would never have gone through with it. "But not you," she says.
Rick and Daryl search for Merle and Michonne, concluding that Merle abducted her. Daryl leaves to track them down.
Rick did not use Merle to deliver Michonne to The Governor, Merle made that choice on his own because he realized Rick would never go through with it. Rick himself realized it was wrong to deliver Michonne on "a chance" at safety.
Watch the episode again.
Taking life in no less horrible because someone attaches an "acceptable" motive to it. This is the reason Carol--perhaps the strongest survivalist among the group--is having her crisis of conscience. She has had and/or believed she had every reason to defend or kill on behalf of the group, yet she is now torn apart by her deadly legacy. Motive did not matter--the act of killing goes beyond subjective values.
Carol's conscious has her operating in a normal 21st century world, something that no longer applies and will likely end up getting her, or someone she cares for, killed.
And the strongest survivalist in the group? Please. Unearned praise. Again.
In this world our characters now live in it's kill or be killed. The morality play comes in when it comes to the reasons for killing. This is how humanity was like eons ago before the concept of civilization.
Our group kills for protection and for defense, in this one case they took a pro-active approach and killed a group of people the know to be a potential thread based on a personal encounter experience and the second-hand word they've gotten from Jesus.
And can Carol really do no fucking wrong to you people? I'll admit when Rick or Daryl or others have made mistakes but let's play some recap here.
In Season 6A, Morgan captures and chooses to spare a Wolf, rendering him unconscious and bound. Carol comes up and kills the man. Carol supporters were all for this. The Wolf was a threat, part of a group that was a threat, and it wasn't felt that any useful information could have been gotten from the captured Wolf. Morgan was foolish for his capture. She did what needed to be done, BAD ASS CAROL!
In Season 6B, as suddenly as she switched from abused, timid, former housewife to a bad-ass killer teaching kids about guns in the period of a couple Carol has made the switch again from this bad-ass killer to someone with a conscious who's more reluctant to kill.
She's captured by a people who are members of group we've been told are dangerous, and a person she is close to -Daryl- are dangerous. These people have captured her and Maggie and threatened their lives as well as Maggie's unborn child. These people are part of a group they've just taken part of a major attack on. When Maggie and Carol have their chance to escape, Maggie wants to finish what they started and kill the Neganettes but Carol thinks they should just get out of there and spare them. Even though the Neganettes could potentially track them back to The Hilltop or the ASZ or still be out there as a known threat. BAD ASS CAROL!
Huhh?!! How is it wrong to spare someone and right to kill them in one instance but not in the other? It's virtually the exact same scenario! The only difference is Morgans Wolf was captured, unconscious and bound! He wasn't a threat anymore! And, cool, Carol killed him!
Here, we're dealing with three women who've expressed little reluctance to kill people and are very much an active threat at the end of the episode as Maggie and Carol try to make their escape and now, ehhh, let's not kill them even though they're part of a larger group that's a big threat.
Seriously, Carol Lovers, your loyalty is now contradicting itself.
