I can't log in to the MK SHIN site. It says I'm not logged in and gives me an error, so I'm going to submit this bug here... maybe someone wants to copy it and paste it. This is for arcade UMK3, it may work on home versions, someone should try it and reply here.

I figured this out using player two side, not sure if it makes a difference. Beat the game or beat the Tounament and pick a Shao Kahn treasure battle (Ermac, Super Endurance, etc.), then have someone join in on the first player side. (I figured this out, becuase everytime I almost lost I had someone join in) After beating the first-player side, fight the bonus-battle again (if you almost lose, join in the first player side again and beat them again). After you beat the bonus battle, you'll start at the bottom of the ladder, as though you just started the game, but the picture of the Kombatant on the ladder won't correspond to the one you fight. After about the third battle the game crashes.

It's a pretty pointless bug, but it's something I haven't seen anywhere else.