Among the many, many highlights of Aaron Judge’s Home Run Derby carnage was a moonshot that didn’t count—because it smacked off the girders that form the roof at Marlins Park. That wasn’t supposed to happen.

In his SI.com column, Tom Verducci explains that when Marlins Park was built, they wanted to avoid the confusion and amateurishness of Tropicana Field, which wasn’t built for baseball and which has weirdly specific ground rules for when balls frequently bang off the various levels of catwalks above the field. The Marlins wanted to make sure no ball would ever hit their roof, so they mathed it out:

Back when the engineers from Walter P. Moore were designing the retractable roof of Marlins Park, they set out to determine how high the roof would have to be so as not to interfere with balls in play. They studied the air density and temperatures of Miami and plugged those variables into equations from NASA. Then they wrote an algorithm “to generate a volumetric approximation of all the possible batted ball flight paths” and then applied it to their Building Information Modeling to determine the final geometry of the roof structure.

The engineers finally arrived at a height of 210 feet above the ground at its apex (above second base) to make sure no batted ball hit the roof. It tapered to a low of 128 feet above the ground in deep right-centerfield.

The Marlins were forced by MLB to come up with ground rules on the off-chance someone came along that the models couldn’t anticipate. Their solution? Any ball that hits the roof at Marlins Park is still in play, oddly enough. It can even be caught for an out. It sounds like they half-asssed the rule because they didn’t expect to ever invoke it.

Well, you know how things went on Monday. Judge hit the roof twice, once in batting practice and once in competition.