This episode contradicts the story Joe told in the Season One episode, A Hero Sits Next Door
, on how he ended up in a wheelchair.
The original story involved Joe stopping The Grinch from stealing toys from an orphanage with the Grinch throwing a skate under Joe causing his fall from the roof.
When Glenn asked him about this, Joe explained it by confessing the Grinch story was made up.
He lied because he was ashamed he let Briggs escape.
It should be noted that it is highly doubtful being shot in the legs seven times would cause paralysis.
Certainly, if the damage was extensive enough, Joe would have walked with a limp but considering paralysis is caused by either brain or spinal cord injury, being shot in the legs would most likely not
result in being completely paralyzed from the waist down.