Follow the mudflat.

With a pitiful groan, Vivia pushed herself off her knees and to her feet, drawing a sharp breath as her footing came up slippery. She was saved only by the depth of the mud, having sunk to her ankles in her struggle for balance. It took a hefty ounce of frustration and grit each time she pulled one boot out of the sucking slime, but soon she managed to start on her way across the flat.

The chill of the ensuing night graced her muddy skin, quickly felt through the soaked fabric of her soiled clothes that clung to her body uncomfortably. Her breeches began to chafe, and she paused to roll the legs up as best she could, a vague feeling of the ground shifting around her mired feet giving her further pause. Once her relatively unsullied knees were bared, she continued slogging through the muck.

She hadn't made it ten strides before that shifting sensation returned. The ground was by no means stable underneath the mud, yet this movement felt as though something were heaving beneath the soil almost deliberately. She slowed to register the movement as more than natural, and under her next step there came a distinctive lift of the flat floor itself, nearly sending her sliding back.

She heard it now—a low rumbling sigh, muffled by the mud. Another swell of the ground below her sent her sliding forward suddenly, and she had to frantically flail to regain her balance. When she was steady once more she caught a glimpse of a bubble in the earthen sluice to her side. In the quiet moment that followed she saw another over her shoulder.

Something was underground. Vivia had little knowledge of this environment, and no guesses came to mind, but whatever it was, she knew she couldn't be too careful around it. If she waited, or perhaps tread even slower to her destination, she might avoid disturbing it...

Another subterranean swell threatened to throw her off her feet, and the gurgling that a too-close bubble of mud issued beside her instilled a desire to flee regardless of caution.