Using Kilz on Subfloor for Urine Odor?

A horrible cat odor from the next-door (this is a row home) was suddenly getting though to our basement. After sealing all cracks, joists and undersides of the subflooring out to 1 foot with mortar, foam, caulk, and Drylok, the smell was still as strong as ever. A fellow in a video said that shellac is the sealer to use here. I am nearly overjoyed to report that after 2-3 coats of shellac over everything (including the Dryloked party wall), the smell has finally abated. The product we used was:

Zinsser 1 gal. B-I-N Shellac-Based White Interior/Spot Exterior Primer and Sealer $41.98 at Home Depot (the can may also say Rustoleum - they merged with Zinsser)
It's an ethyl-alcohol based (make sure the ventilation is adequate!) liquid that's as thin as skim milk. With a 1-1/2" brush I daubed it into and over the foam, caulk and Drylok, into every nook and cranny, and then with a wide whitewash type brush I did the wall down to the floor. One gallon covered about 100 sq. ft. in 2-3 coats You don't need to work it like paint - it's not paint. You just need to get everything wet. It dries in 45 minutes and then can be recoated. We put the recommended two coats on, and then for good measure a third in the areas we suspected were the prime offenders (when the whole room stinks, it's really hard to pinpoint the source).
After all I was glad the surfaces had already been sealed with the Drylok. I think a lot of shellac would be wasted if it went on a porous surface. I believe they can tint the stuff. Putting white on white, I had to rely on the wet shininess to see coverage, and I do believe that absolutely every square inch must be sealed for it to work.
Having sealed every hole, no matter how tiny, the wall is now airtight, and the shellac seems to live up to its promise (I think there's a money-back guarantee on the stuff). There is nothing more demoralizing than spending lots of time and money to refurbish a place, only to have it made uninhabitable by this most foul of smells. We wish you the best of luck.