I'm not sure which episodes you may be looking at to come to that conclusion, Persona, when I look through my DVDs of the series, I notice there just aren't very many episodes after "The First" where Jack is even in the episodes. One notable episode "Interview with the Hulk", one of my favorites, does have the Hulk, once again, saving Jack's life (nice catch!)

Afterword, Jack is noticably shaken, but who wouldn't be with such a close brush with death? As I look at it, he just didn't seem very concerned about what would happen while he was breaking down David's door, or seem particularly terrified of the Hulk, even while while in his grip.