Cat urine in subfloor

[Michelle C.]

I'm getting ready to sell a rental property and the tenant let his cat urinate all over the carpet upstairs. I've pulled out all the carpet, padding, baseboards, and in some areas parts of the drywall in the impacted areas. Painted nearly everything on the floor and baseboard area with BIN primer. However, the plywood subfloor in the closet of the second bedroom smells awful. I soaked it liberally with a good quality enzyme cleaner, but it didn't do much, I then put several coats of BIN primer on it, but if i put my nose down to the floor I can still smell it, however the room doesn't smell any longer. My contractor doesn't think it's a good idea to remove the subfloor because its on a second story of a townhouse and the area is right up against a common wall between my unit and the unit next door, and to a bathroom. My next plan was to bring in an ozone machine. Would throwing any OdorXit on top do anything at this point? What about doing a layer of Kilz? More layers of BIN?