Don't worry, no poo water will be spraying at you. If anything it will be fresh water from the supply line. I haven't gotten sprayed with poo water yet either....
Just one tip. If the supplied hose is too short, they tell you you can send it back with return postage and they will then send you a free longer hose. Well, being impatient, this was not what I wanted to do. So I headed to bunnings to get a longer hose which cost 7 bucks. It still wasn't quite long enough, though and I realised I could actually use my original hose!!!
Not sure if that makes sense to you. I might once you start installing.

Saša