Hm, well, if you really think about it, anything you write that is fiction is somewhat contrived. After all, its about setting up and manipulating events to make things happen. I think 'contrived' happens when you make a character do something they might not naturally do.
Probably the contrived notion here comes from the fact that a lot has happened in a short time and erika is well outside of her normal, postured, controled self. Even so, haven't you ever watched someone do something really stupid and its like, you are terrified for them? Erika isn't *really* part of that whole largo-world thing. She just witnessed an edge of it, and because she was paying attention (rather than it happening outside of her attention span, which is what usually happens to, say, piro) she has this panic'd reaction. You, as readers, know that largo and junpei going out the window ninja style is perfectly acceptable. To erika, she's watching 2 people about to hurt themselves (remember that video of that kid who jumped off the roof of the apartment complex into the pool and hit the edge of the pool? yeah, makes you squirm :P)
Hopefully in full read it wont feel so contrived, but i can see how you feel that way. :)