This shouldn't take all that long so I certainly wouldn't stand around trying to boost it. Just loot all the dust bins, hazardous material boxes and mouldy sofa's and you should get it in no time. Also you get one every time you go toilet, and if you're going for the 100% there are 21 separate toilets you need to poo in regardless for the crappin forte achievement so I wouldn't worry too much about this one.
I uploaded a quick guide that pretty much runs through just this
Lets keep on cheevin' together!