Better in an active streamway than many other places, though obviously not ideal. As for the Daren drum, fine if you have an empty one with you, or if you've brought one specifically as a toilet, but fir an OFD trip, if I expected to need one, I'd probably have gone beforehand, rather than taking in a tub...
You've also just reminded me of the time I needed to poo in Ireby. I managed to get to the downstream sump and assumed it would be long gone before anyone went near it. I found out that evening that Tony Seddon had dived it about half an hour later, while I was off digging. It took me years to own up to it, but Tony didn't remember seeing a poo, or getting ill, so I got away with it! 🤣