He brought an underwater gun and is now underwater but he doesn't really have anything to brace the core against. Some of them will go down to knives. While tribbles hammer on the shield, he pulls his and brings it down hard between a stripe of tiny opalescent scales and a blob of cashmere fluff.

The knife goes right in and the core shudders and deflates and the first cracks in reality begin to appear.

The portal's right there. Time to get out of it.

Ooooh, pretty...

Peeler tugs his arm.

...ah, yep, time to go. 

Kevin should for safety reasons be out of the ocean of tribbles last; Traceless slips past him.

You can't really breathe a satisfying sigh of relief in a scuba mask so that will have to wait a moment.

The griffin is right where he left it. The sheep is successfully breathing water. The cageful of tribbles - aren't? - he's not sure - "Watershed are the tribbles breathing -"

They are not.

Well then he's going to book it up to the surface, box of tribbles first.

Huh. Well, hopefully that'll be okay? 

...Peeler swims up after Haru to see if she can help. 

"Give me some space, the dungeon might take another ten minutes to die and I don't know if they bite, I'm going to be using my power so they don't notice I'm trying to resuscitate them," he says, dumping the tribbles into his box that he stores his underwater gear in. (It's presently almost empty, since he was just underwater and hasn't de-geared yet.) He starts inspecting tribbles for signs of life, one by one, sparing a glance to the sheep and griffin, who are wet but breathe air once they're above the surface.

Ah. Yeah, that makes sense.

She backs off and goes to give Kevin some low bandwidth guiding. 

Yes, Watershed will also be collecting some hugs from her partner now.

He squeezes water out of tribbles. He does not actually try the Kiss of Life though he looks pretty tempted. He does squeeze hard and then haul on the fur to try to reinflate his test subject with air. Monsters are tougher than animals of the same kind; there is no "same kind" for tribbles, not really, but still.

Eventually he gets a calico tribble to purr, and he relaxes and reimplements that procedure on the next one.