Kirby was able to make it into the shelter before Raymond Sullivan sealed the doors after Chuck Greene and his group made it into the shelter. Initially, he is very upset and can be found sitting against the wall, crying.
When the shelter is breached, Kirby is seen being attacked by a crowd of zombies, but is able to defend himself long enough for the emergency doors to be resealed.
Bizarrely, his notebook number is grouped up with the survivors who died in the Introduction. Combined with the fact that his notebook description is also identical to what is used by those survivors, it's possible he was originally supposed to be a arena victim.
Kirby has a unique voice type, as his voice type is 26. In Off The Record however, his voice type is 113.