He's never done this before? Yes, as others said -- he needs to see the vet ASAP. Cats by nature are tidy with their feces and urine and if he did this, something is wrong, either physically (the likeliest answer) or in the cat's mind (it's spraying to mark territory because it suddenlyfeels threatened, or there's been a change in the household that upsets it somehow, etc. Have there been any changes? Ones that you think are no big deal could make an animal feel it needs to re-establish its territory.).
I'm appalled at the two people who immediately posted that getting rid of the cat was your option. After ONE incident? When the cat may be sick and needing care, not punishment? They seem to think one peeing problem is enough to justify throwing out an animal that's been in your home and in your care for four years. If they have cats, I hope they re-home their own cats to owners with more compassion--owners who don't think a living creature can be thrown out like trash.
For the speaker, contact the company that made it. Don't let embarrassment stop you from telling them what happened. I guarantee they've heard it all and can tell you what to do to clean it or replace just the screen on the front of it. For the carpet, contact a pet supply store ASAP and tell them what you need. Be certain to pull up the carpet and clean, or even replace, the padding beneath; you may also need to treat the concrete or other flooring under the pad. It's easy to slice out a small section of carpet pad and insert a replacement of the same thickness; you don't have to replace the entire pad for the whole room. You have to deal with the pad, not just spot-clean the carpet, or the smell will remain.
Someone said to leave the urine there so the cat will smell it and maybe not do it again in that area -- No! The cat would recognize that as an area where it's OK to spray AGAIN.
But meanwhile, please try not to be so angry at the cat. It was behaving in a way that demonstrates a need -- it wasn't intentionally trying to get you angry.