"The water isn't bubbling anymore," Kendra said after bringing her head up. "It feels cooler."
"The temperature is dropping," Tanu remarked. "The potion isn't stopping you from perceiving the heat. It just helps reduce the damage."
"This feels like a medium hot tub," Seth said, eyes upward.
"Won't matter what temperature it is once it fills to the ceiling," Vincent muttered.
"The ceiling is irregular," Trask said. "We've got sort of a chimney over by that corner." He pointed at a square gap in the ceiling. "Hard to say how high the shaft goes, but we should get under it. That will be our last resort."
Mara popped up near the wall above the submerged entryway. "Water is still flowing in. I checked around the entryway but found no keyhole." Without awaiting a response, she ducked back under the water.
Kendra scoured the walls and ceiling, searching with increased intensity as the ceiling drew nearer. Berrigan, Elise, and Mara surfaced periodically, reporting no success. The temperature of the water continued to fall until it was barely lukewarm.
"Tiny perforations in the ceiling," Vincent remarked. "See them?"
"I see them," Trask confirmed.
"Those teensy holes mean this is a death trap," Vincent said. "The air escapes through the holes so the room can fill up without forming air pockets."
"I guess you don't have any anti-drowning potions," Seth said.
"Don't I wish," Tanu chuckled darkly. "We might try a gaseous potion, but the effects won't work underwater, and I don't think those holes are big enough to use as an exit, even as a gas. Your form could get too dispersed, and that would be the end of you. As a last resort, I suppose we can try. You and Kendra each have a gaseous potion, and I have three extras."
The smooth ceiling was now within reach. Trask called Berrigan, Elise, and Mara over to the canoe the next time they surfaced. All three looked exhausted and waterlogged. They positioned the canoe under the square gap in the ceiling. Kendra stared up. The sheer chimney would accommodate the canoe if they kept it at a diagonal, from one corner to the other. She could see the ceiling at the top of the shaft, a long way up, glossy and smooth. It felt like she was gazing up from the bottom of a well.
As the water level reached the ceiling of the room, the little group drifted up into the shaft, clinging to the canoe. With considerably less volume, the shaft filled much faster than the chamber below. The canoe carried them upward at an alarming rate. The top rapidly drew near.
"I don't see holes in this ceiling," Tanu said. "So much for the gaseous potion."
"I see an offshoot near the top," Mara declared.
"You're right," Kendra agreed. "A little shaft branching off to the side."
"We'd better flip the canoe," Trask said. "It will create an air pocket. Tanu, grab the key."
Once Tanu had snatched the iron egg, Trask flipped the canoe. They all kept hold as the ceiling approached.
"Don't go under the canoe until you must," Trask ordered. "We'll deplete the oxygen soon enough."
"I'll explore the side tunnel," Berrigan said. "Give me the key." Tanu handed it over. Berrigan scrambled inside as soon as the water level reached high enough, wriggling forward on his belly due to the cramped confines. Water slurped into the little tunnel behind him. An instant later, the side shaft was flooded, and the bottom of the canoe bumped against the ceiling. Kendra raised her chin, her nose brushing the ceiling as she inhaled a final panicked breath before the water filled to the top.
Holding her breath, Kendra stared after Berrigan. He disappeared around a corner in the side shaft. The water felt cool now. Vincent swam into the overturned canoe. Trask motioned for Kendra to follow.
Her head came up in the enclosed space beside Vincent, who was panting. The air smelled like wet wood. "This is our only air pocket," Vincent complained. "Not a bit outside. There must be holes somewhere, in the corners or something, maybe so small we can't see them." He paused as if an afterthought had occurred to him. "Or maybe the place is simply unnatural." He gave a thin chuckle. "I guess now would be a bad time to mention that drowning has always been my greatest fear."
"It was never a goal of mine," Kendra said, trying to stay brave.
Seth surfaced inside the canoe. The others surfaced as well.
"No sign of Berrigan," Mara said. "I'm going after him. There's a chance this little tunnel leads to a way out."
"Go," Trask agreed. Mara dove into the side shaft.
Trask looked from Kendra to Seth. "Unless they return reporting a dead end, once the air goes stale, we'll follow."
Vincent had his eyes squinted shut, his lips moving soundlessly. Kendra trembled. There were too many heads inside the little air pocket under the canoe. The air would soon go bad. What would drowning feel like? Would she pass out before she inhaled water? Would inhaling liquid instead of air provide any consolation, any illusion of breathing? She didn't want to know. She tried not to think about it.
"What a way to go," Seth mumbled.
"We're not dead yet," Tanu said.
Kendra ducked under the water and stared into the shaft. Mara was already out of sight. Kendra stayed down, watching hopefully. Mara shot back into view, returning swiftly. The water level began to drop! Kendra screamed with joy, the sound distorted in the water, bubbles rising from her lips. Mara hurried forward. Kendra glimpsed Berrigan behind her. Then the water was dropping fast enough that the side shaft passed out of sight.
Kendra surfaced. Trask and Tanu righted the canoe, and everyone grabbed hold. Mara dropped from the shaft, entering the water with her toes pointed and without hitting anybody. A moment later, Berrigan hit the water the same way, plunging through a tight slot between Vincent and Trask. Soon Mara and Berrigan clutched the canoe as well.
"There was a keyhole at the end of the tunnel," Berrigan said, holding up a smaller iron egg. "This place was designed by very cruel people."
The canoe dropped out of the shaft, and the water level continued to fall rapidly. Despite her excitement, Kendra's teeth began to chatter. The water was becoming truly cold.
"The water is flowing out faster than it came in," Mara said.
"Just what I need," Vincent griped, "to get sucked down a giant drain."
Kendra watched the walls, hoping a new tunnel would come into view. The water level kept plummeting.