wp_query->query_vars

I followed the instructions in adding new query vars to a plug-in I’m making but the following problem is making it impossible for me to advance

after adding ?authors=&pages= queries I can only run them in a template. I don’t know why but I can’t capture them in the plug-in. Example

in the template I just use isset( $wp_query->query_vars[‘authors’] ) but when I do that inside the plug-in code its not even set, instead it creates a new instance of the object. (which is completely resetted)

So to sum it up I can’t capture with wp_query inside the plugin, any suggestions on where to approach?