Floorpan Rust

Nothing you can do really besides cut them out and start prepping for new pans, the guy who had my Dart was driving it with them like that and it needed a trip to the frame machine to get the unibody straightened back up before I installed new pans.

I would cut them out to prevent the rust from spreading and it will also give you a chance to clean out the rails and kill whatever rust is in there while you're waiting for pans.