A Man Suffers a Heart Attack on the First Flight of 'The Amazing Race: Unfinished Business' (VIDEO)

No matter how hard you prepare for 'The Amazing Race' (Sun., 8PM ET on CBS), you simply can't prepare for the unknown. And nowhere does the unknown seem to rear its ugly head more than when it comes to the myriad flights contestants must take.

At the beginning of this season, which features contestants who've raced before but never won, host Phil Keoghan said that second chances don't come easy. A few short hours later on their very first flight, that proved to be even more true than they might have imagined.

After an opening challenge saw eight of the eleven teams secure a position on an earlier flight to Australia -- with a 90-minute lead on the second plane -- the unexpected occurred. A man on the lead plane had a heart attack mid-flight, causing it to make an emergency landing in Honolulu.

Instead of arriving early, the eight teams that finished the challenge first arrived 30 minutes after the three other teams. It established right away that you can never sit comfortably in 'The Amazing Race.' As long as you are racing in the real world, anything can happen.

Thankfully, the man who suffered the heart attack was all right. But you just know those 16 racers on that plane were frustrated just the same to see their first lead in the game evaporate just like that.