You went with Merle, T-Dog, Andrea, Morales, Jacqui, and Glenn on a supply run to Atlanta. But it didn't go too well.
You ended up stuck in a building, and thanks to the new edition from a sheriff named Rick Grimes, Merle ended up handcuffed to the roof.
Rick and Glenn had covered themselves in Walker's blood to go and get a truck. The last door to the shop you were in broke, and everyone started to rush out to the garage. You were waiting for T-Dog to come back with Merle, but when did come back down the stairs he was alone.
“I dropped the key down a drain! We gotta get outta here!” T-Dog said, rushing for the door as the Walkers started to flood in. You were about to follow him, but that would leave Merle for dead, and as much as he probably deserved it, you couldn't just leave him to rot.
So you ran back up the stairs to Merle, even if the others would leave you there.
Merle was sitting on the roof, yelling, because he thought all hope was lost. He thought he was a goner, a dead man, but then he heard the door open and shut again.