That they didn't leave him behind and actually were attacked by the wolf people and eaten or something and that Haiji lured him away to save him. Maybe Shiro forgot due to trauma.
Bada isn't an NPC but a player stuck from a previous game, like the cam corder was the saving item for game A and the cassette player was the save item for game B (doha and them), and Bada maybe was sacrificed by team A so he became an "NPC" in Team B?
Everyone is beautiful wth?