You travel about 60 feet down this 5 foot wide passage, then it turns to the right. Glabbagool squishes out into the room below with a loud slurping noise. It moves across this room and settles in the southern part, moving out of the way to allow the party to enter. The cube proudly says "This room has choices!" 

As Glabbagool enters this space, a wave of water pours around him and starts running down the various passageways. The area where you're standing is now about 2 feet deep. What you can see is that this chamber has four narrow openings in the west wall that all lead down different passages. Opposite those paths, on the eastern side of the room, a natural passageway has opened up. Rocks and debris litter the floor, making it appear that this wall recently fell in. You can definitely tell that the large volume of water is coming out of this passage to the east. 

Bringing up the rear, only if no one else picks up the coins and mace, then Tanis does, though he offers the mace to Kisiki (or maybe Vrah) as he himself has no use for it.  The coins - Tanis states (truthfully) that he will share them out among the party when there is less urgency to escape a watery death.

"Thank you Glabbagool." (I seem to be saying that quite a bit, Tanis thinks.) "What is down these four passageways?  Is there a way out, maybe upward above the water?  Or just more oozes?  I seem to sense that most of the water is coming from the eastern passageway that looks much more recent.  Like it only just recently opened up.  Did it?  Have you been that way before?  Maybe we can block or bypass the water if we go in that direction."

(Assuming the party can get past Glabbagool to the eastern natural passageway.)

“Which way is out?”  Is our cube friend absorbing the water?

Glabbagool did move into the room far enough to let you all get around it. It's in the southeast corner staying against the wall, out of the way. The cube is not noticeably absorbing any significant amount of water.

"Eastern passage is new. Not been that way before. Other passages too skinny. Glabbagool not like. What is out? Is that where you come from? The land of Out?"

"If the water is getting in, then maybe we can get out..." Vethna comments, glancing to the others. "With how fast this place is filling, I am not sure we have time for anything but getting out of here..." She nods to the eastern passage. "I vote we go towards the water and see if we can get out that way."

Vrah is reluctant to follow the ooze, but as there is no other way, he agrees, but stays toward the back, making sure nothing is following them.

As for the mace he responds he is used to fighting with two weapons but he lets Kisiki decide as he prefers bladed weapons.

Vrah will go down each passageway about 15' to see what else is there, but before he goes, he asks Glabbagool , "Any of your type or other oozes down passageways? Want to see which direction is best to travel before we decided."

Glabbagool responds "I see other things like me around here, but I don't know where they live."

As Vrah goes down the first passageway about 15 feet, he can see 10 feet ahead that it turns slightly to the left at a 45 degree angle. 

As he goes down the second passageway, he can likewise see that up ahead it also turns slightly to the left, running parallel to the other passageway. As you pause and start to turn around to backtrack... the floor of the passage begins to crumble underneath you. 

Vrah needs to make a DEX save. 

Kisiki waves off the mace. "My claws are stronger than this." He's happy to see it go to a good home with Vrah, though, "Take anything of use. If one of us is stronger, we are all stronger."

The lizardman does not seem at all perturbed by the sentient ooze; in fact, he seems to hold it in some esteem. He looks at it in the same way he looks at Shoowaa's tail. The water rising around his legs also does not seem to bother the giant shaman; he seems quite at home in the rising murky waters.

Vrah Dex Check: 19

Vethna has moved to the eastern passage and is scouting down that direction.

The floor of the hallway collapses under Vrah, revealing a ten-feet deep pit. The bugbear is able to spin quickly and grab the side before falling in. 

Vrah: Make a strength saving throw to pull yourself out with the water rushing around you. If anyone comes to help, you can do so at advantage.

Vethna, as you move down the eastern passageway, it opens into a small chamber. Water is pouring through large cracks in the ceiling. This is where the bulk of the water is coming from. You can't tell the source, but based on the volume of the flow, it must be a large amount of water, enough to fill up all these passages in a few hours.

Vrah Str check: 18

Vrah scrambles out of the pit. Even with the water rushing in, you think you hear a slurping noise coming from below. 

Tanis backs towards the eastern passageway that Vethna is already scouting, arrow knocked to longbow in case something comes out of the pit.

"Vrah, everyone, get back east here away from the pit!  If it's an aggressive ooze, better to attack at range.  Glabbagool, the world is much bigger than this temple and we are trying to get back out to the rest of it.  But it's harder if these other oozes keep attacking us."

When everyone has a chance, let me know if you move into the eastern passage where the water is coming from or stay in this room with the multiple hallways coming out of it. 

"Other passageways not safe, eastern one is only way out, lets go." Vrah says as he dusts himself off from almost falling into the pit.

(To elaborate on post 1316 above, Tanis is facing back towards the room and the four narrow passageways, including the one Vrah initially ventured into.  Arrow nocked to bow.  But he is backing into the eastern passageway, trusting the lead scouts like Vethna to warn the party if there are any hazards that way.  Trying to stay in the darkness to so he is Invisible to darkvision due to Umbral Sight.)

Shoowaa will go to the eastren passage. "You want to come with us, Glabbgoll?  There is more space out side of the temple!"

Kisiki points down the eastern hallway. "The secrets will reveal themselves to us deeper in the temple. Semuanya brought us here for a reason."