I don't know why everyone keeps debating the difficulty and ability of players to play the game properly when it has absolutely nothing to do with why people are exiting upon entering. They're exiting immediately because every other trial in the roulette takes about five minutes, while this one takes a minimum of 15.

Though they do (or the first person does at least) incur a 30-minute penalty for leaving, that's 30 minutes they can go do something else, even not play FFXIV, so they take it. They were looking for something quick, they didn't get it, so they leave.