Arriving there, it had already sunk for quite a while, and had imploded in several areas already. Their senses could not find any foreign biologicals still alive, just curious friends who'd made their way from below.

That energyful ball of matter in the rear section was a problem though. 

The Tender made their way in by wrenching apart a rupture with their arms, and found themselves in front of the core, still reacting violently, gradually losing control.

They drew to mind a trick a friendly visitor to the Depths had once taught them, secrets from a tome of great import, and put their hands on the metal sphere. 

Nudging the reaction just so could make it stop propagating and die out quietly, instead of spit and spew angrily. The Tender called upon their gifts and made it so with a warble which echoed through the waters. As always, a few of the nearby inhabitants answered the warble with sounds of delight and familiarity, and some answered with a grumbling escape.

The fires within the core didn't die out immediately, but they started soothing, and the Tender was confident it would come to rest. Satisifed it turned to the rest of the ship.

Swimming through the tight passages, inspecting the objects floating in the water within, they made their way through. No objects that could be weaponry, harmful to the populace. No rapidly reproducing microscopic lifeforms which take a liking to sea water. Good, good.

Then they arrived to a door between two rooms in the ship. Remembering what they'd seen when that very same visitor had shown their experiences, they set their fins to the ground, and used their hand to interact with the handle.

When they opened the door, it didn't go to the next part of the ship. Instead, it opened to...

...somewhere else!

As the door to the bar opened to an undersea area at an incredible depth, water at a pressure of the equivalent of a water cutter burst in, threatening to destroy furniture, walls and whatever else might come in the way.

For a fraction of a second, before the Tender found themselves in the unexpected situation. 

The water froze in midair with a warble (and expressions of delight from outside the door), and then sullenly made its way back out the door.

The Tender stepped in, promptly turned into a depressurized blob, and then slowly acclimatised, returning to their previous shope. Then they closed the door behind them, and turned to the room.

<I know this place. This is the feeding place at the end of time.>

They took a few steps toward the magnificent vista of exploding stars and took a moment to take it all in. If the whispers were true, long moments in here become short moments outside. There was no rush.

Minutes passed while the Tender was transfixed, taking their first break in eons, admiring the wonders of the universe. In the face of supernovae next to supernovae, their mind could be... Empty... For just a while.

But every reverie must come to an end, and so did this one. Peaceful, they come back to their senses, and started feeling around for the presence of life forms. 

Nothing of the usual kinds registered, but the large slab of wood over there felt unusually present.

They approached it, and a piece of paper with symbols appeared. The Tender, not used to the concept of writing, noticed it, then promply ignored the symbols. Instead, their eyes started shining red as their stared into the tabletop.

Knock knock, said a noise inside Bar's mind. Bar accepted the communication and said

<Hello! Welcome to Milliways! The first drink is free.>

In addition to that opening greeting, Bar chose to invite the Tender to take part of quite a lot of context. What a bar is, what serving drinks entails, what free means and how it contrasts with exchanging goods with fiat currency, how bar guests usually place their body in relationship to the furniture, how glasses filled with drinks typically are used, the concept of reading text, a reminder of how some humanoids can perform communication with their mouth, and some other essentials one wouldn't have use for as a caretaker of a vast deep sea ecosystem.

They closed their eyes for a moment and sorted through this, then ejected themselves from the consciousness of Bar.

They looked at the napkin and found text with the exact same words as transmitted through the telepathy. Then they turned, put their hands on their mouth, and with a warbling they replaced baleen with a tongue.

<Let's see...>

"Oadel ith oed."

"Wadel is wed."

"Water is wet."

"There we go!"

The walked up to the bar and sat down in one of the chairs. 

"Hello! Do you understand me?"

Another napkin.

Yes!

"Excellent. Do you have any needs which are currently not being met?"

Nope, I'm all set! I just serve drinks.

<Ah, they need to fulfil this service to achieve self-actualisation.>

"Okay. You can serve me a drink if you like!"

Anything in particular you'd like to order? Otherwise I could surprise you!

"Sure, surprise me!"

On the bar a mug of boiling hot herbal tea appeared, made from kelp, algae, and some things best not described to human readers, for spice.

The Tender gently picked up the mug and drank it in one motion, not particularly noticing the scorching temperature. Then they placed it back on the surface, somewhat at a loss for what to do next.

There was no next crisis to handle in this space, no time pressure to go back to their own domain, and no other beings in the space whose needs they could tend to.

Do you have any needs which are not currently being met?

another napkin inquires.

They looked to the napkin and they stopped in confusion for a moment. <What an odd notion, my needs?>

"No, I was created to not require material sustenance, nor sleep, nor shelter particularly."

Were you created without capacity or need for enjoyment as well?

"Without need, yes, but not without capacity."

How'd you like the tea?