Title says it mostly. I accidentally walked in on my dad going down on my mom. This just happened like 15 minutes ago

I was playing Fallout 4 for several hours, and I had no clue where my parents were. Keep in mind, that I also have a hearing deficit and I was not wearing my hearing aids at the time. On top of that, it is currently very late where I live so I figured my parents were in bed or something.

After playing Fallout 4 for several hours, I go into the hallway and I see a small amount of light coming from the game room. I thought that maybe someone left the TV on and I went to turn it off. I open the door and lo and behold...

My father's head is in between my mom's legs, like 6 feet away from me. I just shut the door and ran downstairs and outside. I became a little concerned about what would happen next.

My father came outside, and I asked: "How are ya?" And he said: "Fine, but next time knock."

I explained that not only had I been unaware of where they were, but it was also late and I thought maybe they were in bed. I also mentioned that I was not wearing my hearing aids and could not hear behind the door very well. I also added on top of all of that I saw a light coming from the game room and thought that maybe someone left the TV on and intended to turn it off. I also apologized and said that I just made an honest mistake.

My father said everything was fine and I had absolutely nothing to worry about. He just said that Fridays and Saturdays are the only two days that he has time to spend with my Mom, so I should be more... vigilant about opening a door on those days.

TLDR: I walked in on my parents having sex. My father asked that next time I knock, but he acknowledged that I made a genuine error.

EDIT: Holy F-Word 6k upvotes! I want to thank the people who have given me positive reinforcement so far.

EDIT 2: I am at a loss for words. More than 10K upvotes. My inbox is so demolished that I don't think even Vault-Tec could have made a vault sturdy enough to protect it.