I turned my light on, and studied the side of the pipe. The water was rising. I could see he was already making his way towards me. Panic, like the water was rising fast, and headlines actually flashed in front of me. By the time John returned the volume of water had increased by over tenfold.
Lets get out of here.
I said that I'd see if there was anything interesting in the next few sections before we turned out, since it was getting fairly late. I went upstream as quickly as I comfortably could, so that I could map another couple of manhole covers, and was soon at the end of that section. As was getting back down into the water, after I had adjusted the map, I noticed that the water was flowing faster, than when I had stood up, and that it was now many times higher than when we had entered. This made up my mind, and I turned back towards Bill. As I crawled back, the water continued to rise, and by the time I was back where I had left Bill, I was rather worried about the rate of rise.