My puppy just peed on my parents carpet!!

Oh my goodness they are going to kill me 😭😭 my puppy is 6 months and is house trained idk why he did this. Help!!

I live with them but I meant their room carpet

I keep the back yard door open so he can go whenever he want, I was cleaning their restroom and he saw me. He looked straight at me and started peeing 😭😭😭 he's such a good pup and the back door was open and he was JUST outside.