You take a ladder up to the top

After swimming down the channel awhile you notice a ladder leading but up. You take the ladder. When you grip it, the ladder automatically starts pulling you up. Straight ahead is a large building that appears to be a factory of some sort. You walk inside of it to check it out. Inside metal robots are processing humans! The people come netted down conyeyor belts, they appear drugged. The robots pull the head, arms and legs off and put the parts onto they're own electronic belts. You almost scream out loud!