Fortress 3 (Patreon)

Yuri was holding her breath for several minutes now. As she wasn't a trained freediver or anything, it was remarkable that she was still able to exercise breath control and make judgments. Probably it was a a sense of fiduciary duty as Shina's young guardian. Shina had to be brought home safe, Yuri thought, even if that meant Yuri was not going home.  

After what felt like doing a whole length of a pool underwater, she did see some light ahead - yay! But coming close, she noted that it was only coming through porous volcanic rock overhead. That she was able to see around her was a huge plus but, the hope of being able to breathe quickly turned into disappointment felt like the clutch of a vice on her lungs. Ahh, what a pain!