I agree, her change is due to the shoot out. But I don't think it's because her life was threatened in the shoot out, but everyone else's. With Frankie, her HIV, and the fire, her life was threatened but no one else that she was close to. The only other people who has been seriously hurt/threatened have been relatively unharmed with the exception of Flack at the end of season two. But then I think Stella was so focused on the bomber that she didn't have time to think about anything else. Now that one of her friends has died and another seriously injured, it's starting to take it's toll. Now, I said all that to say this. Personally, I'd like to see Stella totally break down this season. Not because I want -insert perfered male here- to be there and catch her when she does, but because a) I know Melina would handle it beautifully, and b) we've seen minor upsets from her before, but after six years all that emotion needs to be let out.