Frankie Edgar spent almost eight total hours inside the UFC octagon during his illustrious career, but that doesn’t mean he’s not prone to mistakes every now and again.

The former UFC lightweight champion, who announced his retirement from active competition this past November, posted a video on his Instagram account on Monday showing a recent mishap he endured while training with another fighter.

The video shows Edgar backing up during a sparring session, but rather than hitting the cage wall, the New Jersey native tumbled outside and fell to the ground instead.

“Over 18 years in the game and I’m still making rookie mistakes,” Edgar wrote. “Forgot to lock the cage door when I was training Mark Grey and boom! I was expecting to feel the cage on my back but instead I felt the stairs dig into my back and the back of my head into the floor.

“Thankfully there were rubber mats on the floor. Still got up and finished the session, we got fights to win!”

Obviously, Edgar was physically OK after the incident, although his pride may have taken a ding based on his fall from the cage. It appears he suffered no injuries, with the training session continuing afterward — although he probably double checked to make sure that door was secured the next time around.