And turns it back off, cursing internally about how hard habits are to break.

...then he turns it back on, and walks over to the two team members that are already present.

"Do not act startled," he says without preamble, "or react in any noticeable way if you can avoid it. There are monsters here; you can't see them, and they don't seem inclined to attack unprovoked. I can make both of you able to see them but they might react to that." Jaeha himself can't see them, and he is immune to his own shielding, but he can perceive them with his empathy and also detect their work on others' minds.

...well, shit.

"Understood," says the team leader in a firm but not agitated tone. Then she softens a bit. "Thank you, Kang Jaeha-shi. It's always a pleasure to work with you." And a reminder of how insanely powerful this man is, he is not the first psychic esper to have come here—their missing team member is one, himself—but he's the only one who's noticed. "I'll add it to the report." Psychic dungeon reports have sections marked as informational hazards and everyone cleared to go into them has training to deal with those.

"Are they the things people have been hallucinating?" asks the other team member.

"I don't know. I'm not seeing them myself, only perceiving their minds." Let them think that this is because he doesn't want to see the monsters; the fact that he can't shield himself isn't public, and he's not going to mention it aloud. "Which is risky enough as-is, so I'm going to stop so that I can't tell where they are and alert them to the fact that I know."

He... is a lot more reluctant to do it now than he was when he'd just arrived. It's useful to have this power. The tactical considerations are correct, though, and it would be safer for him to not know where the monsters are, so he doesn't hesitate very long before closing his third eye.

"What could you detect about them?'

"There are two of them here with us, and I detected at least another four in range. Monsters' emotional makeups are always hard to describe but they felt—idle. That's part of why I'm hesitant to let people see them, it might agitate them."

Undetectable psychic monsters are definitely the kind of thing that'll place this dungeon square in the A-rank category. They're always difficult to deal with, as it's a toss of the dice whether combat espers will even be able to touch them, and their sensory modalities are unpredictable. He can at least rule out straight mind reading, as they didn't react to his finding out that they're here and informing his team. 

"I didn't take a very close look. If they use both psychic and normal senses they might notice anyone who disappeared from the former but not the latter. They might notice direct attention, psychic or otherwise. If they're the main vectors of the hallucinations and nightmares they'll almost certainly notice anything strange happening to any specific people they're currently acting on."

"Once Won Seonwoo is here we can get his thoughts but this sounds like we might need reinforcements."

"Almost certainly."

Their missing party member chooses that moment to arrive. He walks over to them and bows. "Kang Jaeha-shi, it's been a while. Have you managed to deal with the problem you were having yesterday?"

"Problem...?"

"You had unscheduled this dungeon, had you not?"

"Ah." Fuck, Won Seonwoo is impossible to read and Jaeha has no idea what he's feeling and has to abort the instinctual reach for his emotions but that means he hesitates a bit too long—

"I'm certain it must have been urgent."

"—forgive me, I shouldn't pry."

Aaah what does he do does he smile does he shrug does he distract—

"Don't worry about it," which is the least confident thing he could possibly say here but it's at least the safest.

"More importantly, Kang Jaeha-shi has detected monsters hiding their presence here, and it's a safe bet there are more."

"Would you be able to check how safe it would be to...?"

"On it," he says, eyes going unfocused. "...not very clear. Can you form more firm intentions...? Ah. That would have mixed success... that would work better... that would not work well at all."

"They can't directly perceive that they're being perceived as a primitive action but they're very atuned to people's actions and reactions, is my guess. —letting all of you see them, only seeing them myself," sort of, "and letting the support team see them. If—"

"Oh that would be a disaster," he interrupts.

"That was me deciding to actively rile them up."

"It always amazes me how good you are at flipping between intentions, Kang Jaeha-shi."

Is that genuine, or is he subtly insulting Jaeha? Won Seonwoo makes him really uncomfortable but at least before he had a handle on the man. His best guess is that it's genuine but there's something in Won Seonwoo's voice...

"Team leader-nim, what should we do?"

"Seonwoo, do you think you can cover the three of you if you go into the dungeon?"