Randall is a ticking bomb. After the way he went after that zombie woman ("Let's see what you've got, bitch"), and kept stabbing her in the head repeatedly, I think he's full of shit and is just as bad as the guys that left him behind. I'm not even convinced he really knows Maggie. Aside from using her name, which he could have easily picked up from the group, he gave no real information to back it up.
Sure, using Maggie's name may have put him one step closer to a bullet in the head, but he may not have considered that while he was trying to talk the guys out of leaving him tied upon the floor in Zombieville. I said he was full of shit, but I never said he was smart.
The sneak preview for next week's show seems to suggest that Daryl is going to conduct interrogation that would make Gitmo prison guards afraid.
If you're right, that may flush out any of Randall's lies.