Actually level 5 is kinda wonky. The tips tell me to rescue captives, but regardless of what I do, it just says this:

    > Oops, looks like there was a syntax error in your code. Try again and click "Grade it!"

Without anything for me to look at. Weird.

I had the same problem, for some reason

    get '/:short_code' do
    end

got inserted at the end of the textarea.

It looks like this is because rescue is a reserved word in Ruby (Disclaimer: I'm not a Ruby expert, just basing this on a Google search and the syntax highlighting)