I was doing wanderer's palace, my group was fighting the second boss, the slime boss.
He decided to focus on me, but I waited a bit too long so when i tried running away from the boss he managed to hit me.

The weird part is once the boss hit me with his swirl attack, some how it must've triggered my mount. My mount is bounded to "ctrl -". not only was i able to get onto my mount in a dungeon, but it also happened in the middle of the fight, and it also happened instantly upon getting hit by the boss there was no cast bar for it either.

Anyways it was pretty funny that somehow my character mounted onto my chocobo midboss fight in a dungeon.