Parents argue. Sometimes they argue a lot.
This has nothing to do with you though. Don't you have arguments with your friends at school from time to time?
Does that mean you never want to see them again?
Parents argue, they spend some time upset with each other, then once they've cooled off they patch it up. I do it fairly frequently with my partner.
Adults are usually better at hiding the fact that they're upset, but sometimes this isn't possible and they need to let their feelings out.
Although it might seem scary when your parents fight, it's actually a healthy thing.
Imagine if they never spoke up when one was annoying the other? They'd have to keep it all bubbled up inside until it was too much to handle and their heads would explode! (figuratively speaking)
Anyway, my point is all parents fight at some point. It's pretty normal. And there's very little you can do to stop it happening, so it's really not your fault at all!
And yes, some parents get divorced too, but that usually follows months or even years of fighting and arguments and complex issues like infidelity or alcoholism that you probably don't need to worry about... So I think you're safe here, one little argument isn't going to bring their marriage down.
My advice would be to act upset and make them feel guilty for fighting.
Not only will it make them think twice about arguing in front of you, but it's a good way to blackmail something out of them (like extra pocket money or a PS4 or whatever kids play with these days...) They'll be feeling too guilty to say no.