Two things:
1. They didn't have enough time to open the train door to let that kid in? Are you freaking kidding me?!?
2. With as many walkers as they killed in the train, there should have been a mountain of dead walkers, but the aisle stayed clear.
2. With as many walkers as they killed in the train, there should have been a mountain of dead walkers, but the aisle stayed clear.