Cat urine smell

Hello all, Unfortunately my roommates cat used the bathroom outside the litter box when he was stressed out. (No need for a vet). Now the entire apartment smells like urine. We have searched all the spots and tackled it with oxynclean, dawn, hydrogen peroxide, and odor eliminating enzymes (at seperate times) but nothing seems to be working. Any advice? I am beside myself with how much it stinks and it's causing tension in the home. He is trying his best, but nothing seems to be working. I can't live peacefully when my face is melting off with all the smells.