The only truly safe way is with a tire cage and a fill hose with a clip-on chuck that gets you away from it.

Better is at least the tire standing up with a long fill hose. Mounting tires with the wheel laying on the floor makes a launch pad if anything fails. Our old shop had a patched hole in the roof from where a steel ag wheel failed and exited the building. With them standing up the air can better escape.

Search YouTube for tire explosion or tire cage explosion. Most of the videos are semi or construction tires, so somebody's going to say race tires don't have that much force. Yeah right, but when you see what they do to massive tire cages imagine what a race tire will do to your unprotected melon.