Cut it loose

Swiveling your head as you see the walls closing in, you quickly begin to hew at the pillar just above the crystal. After 10 or so good thwacks, the bottom half of the column falls onto its side under the auspices of gravity. The walls are getting closer. With even better positioning, it only takes two good cleaves to fully separate the gem. You can hear the scream of the creature as its energy source is torn from it. You quickly aboutface, scoop it up, and begin running for the exit, sheathing your sword as you do so. You hurdle over lumps and appendages, and duck beneath even more limbs. You quickly dive into the water at the end of the passageway, swimming for life for the surface. Once you finally break the surface, you waste no time getting on dry land. You crawl up the shore and get on your two feet. You watch as the creature extends out of the water. You quickly get away from the trench and head back towards the trail you took to get here.