The problem with that is you have to get them near a toilet in the first place. If you were on Xbox then you might have enjoyed a series of contracts I did called Devious Drownings (I think there were about seven in total). They all happened in Sapienza and each contract involved two targets. The methods had to be, as the title suggests, devious.
The puzzle master @Ed_ll3 solved each one of them with typical flair and creativity. You could probably find videos for each one on his YouTube channel if you were interested.