Rust help

I was told because my floor pans are pretty rusty that I would have to remove the rust to see if the metal underneath is any good this picture is one that I took after hand brushing with a wire brush do I need to remove further rust in the center of the picture or is that enough. Yes I know the area around the shiny bit is still rusted but I'm doing it by hand and was looking for some advice. Thanks in advance.

1000002256.jpg