Walking Dead: Behind the Dead (watching now)

He was bitten on the prison grounds, but not inside. There was
a walker invasion ... this is from a WD wiki somwhere ...


While helping Carol to park the group's vehicles inside the prison's courtyard, a walker invasion begins. T-Dog notices that a gate was opened and the walkers are pouring in through it, he then rushes through the walkers to seal the gate once again.

While doing so, he ends up bitten in the shoulder by a walker, after killing it, he and Carol run inside the prison to save themselves.

T-Dog decides to use his last hours of life helping Carol to get back to Cell Block C in safety, ignoring Carol as she tells him that he should rest because of the bite, they reach the corridor that takes to the laundry room, but it is blocked by two walkers. Carol insists that they should go back and find another way, but T-Dog heroically charges the two walkers against the wall and tells Carol to escape while she can. Carol runs to the laundry room, when she looks back, the two walkers are tearing into T-Dog's body. "I'm dead, just go!" he says.