She's - cranky about attempting therapists, or perhaps guarded and wary, so she focuses on something she's really really good at instead. That being dungeons.
As dramatic as sending Hye-jin alone to kill a dungeon is, it's not really the norm. She doesn't need any kind of martial backup, she's fully capable of destroying a dungeon on her own, but being directed and supported means she spends less time wandering around and more time being a one woman demolition and firepower team. There are usually teams of (armed and trained) non-espers trailing along behind her to escort rescues to the exit, or direct her to pockets of monsters she might've missed on her own, or relay updates from the dungeon's central command.
She burns through the lock on the door of the last kidnapping victim of the psych-ward themed dungeon, kicks it open (because it's fun), and steps out of the way of her minions assistants to let them do the fiddly bits of freeing the poor soul from the straitjacket the dungeon stuffed them in.
"That's the last one?" confirms Hye-jin, on her comms.