You do not lose out on any chance to retrieve the bonus if someone -or even you- quits from the trial that you're currently running. You literally either just wait your penalty time or just hop on back into the roulette and you'll get the bonus then.

On the same note, I hate tanks who just leave whenever they see a Ravana HM or any other trial that they don't feel like doing. Don't wanna do any trial that you may get besides Garuda HM? >_> Don't queue and then leave and ruin it for the rest of us.

But yeah, even if you have to leave, you just requeue again and get the bonus.