Punters meeting now and then is almost impossible to avoid in a parlour unless you have cubby holes to hide them in.
In my experience if when entering you make it clear to the girls you do not wish to see or be seen by another punter I'm sure they will try their best.
Had someone walk in mid hand job myself years ago at bubbles in Derby, we all just looked at each other, he said sorry, left, and we got on with it.
Accidents will happen.
You're right about Zoe, one of the best girls there always have a good time when I see her.