Escape...

Despite your shock, you react quickly, sitting up and yanking your knife from its' sheath. As the tentacle begins to pull you, you slash viciously at it, severing it cleanly with one blow.

The rest of the tentacle recoils, the squishing sounds from that pipe not only intensifying, but now joined by a rumble. You scramble to your feet, snatching your pistol out of the water, looking at the other three exits. You can't remember which one you came in from, and there's nothing distinctive to differentiate them.

The squelching intensifies, and you have no time to investigate which pipe to take.