Sorry buddy, but the trunk doesn’tt ” just come out.” It has to be cut out.
if you go to that much trouble, you should replace the floor with a new pan. That would be the Right way to do the job.
But don’t jump to that right away, 1st find and fix the leak or you will be throwing good $ after bad. If the panel is just covered with surface rust and not rusted completelyThuru, you can clean the surface with a wire brush( one mounted to a drill works well and they come in different sizes) and then primer or paint it. por-15 is a great product but is better if the Prep work is done correctly. It is not a fix-all. good luck and remember.to fix the leak 1st.
As the army likes to say ” this is A WAY not THE WAY!” I’m sure others will give you great advice. Peace from Camp Taji Iraq
I use an air powered sheet metal shear on body panels but that will probably be too awkward to maneuver in the tight space turns in the trunk and so I think the best alternative would be an air chisel with a panel chisel or ripping chisel bit.
I’m sure you will be wanting to replace the trunk floor and this looks like a good one and reasonably priced:
here are online trunk repair instructions using KBS RustSeal. BTW, if you like por15, you’ll like this product even better.