IOS Swift pass variables between viewControllers using Segue

I am trying to figure out how to pass variables between two views in an iOS app. My main goal is to learn this so that I can use it in my own project (hint calculator). The code I wrote is in the following github link:

http://bit.ly/1mVra4l

I did everything as described in the following tutorial: http://jamesleist.com/ios-swift-passing-data-between-viewcontrollers/

I faced two problems:

1) When I start the application and click the button, the breakpoint is automatically triggered at the line

       var svc = segue!.destinationViewController as secondViewController;

      

        
        
        
      

    

I'm pretty sure I haven't set any breakpoints anywhere.

2) When I click continue in lldb, I get a crash (EXC_BAD_ACCESS) on the same line.

This problem is driving me crazy. Any help would be appreciated.

I am using xcode6-beta6, Swift language

thank