From NPR:
>One problem we would have here is to calculate the damage because I believe the damage is incalculable and it's going to ripple into the future, because it will cost us convention business and people will be a little ***gun shy*** about ***coming back in here*** if they think this could happen again.<br/><sub>([Source](http://wshu.org/post/charleston-mayor-company-behind-chemical-leak-run-renegades))</sub>

I have two questions:

 1. What's the meaning of *gun shy*?
 2. *come back in here* is a little weird for me. I know a phrase is *come here*, so I think if I want to stress the orientation *back*, I can only add a word *back* before *here*, just as *come back here* (but still a little weird for me). So why does he add the word *in* before *here*? Can you give me more examples?