The Buddha explains to Nagita, his attendant, his refusal to accept homage by a series of images progressively pointing out the disadvantages of proximity to society and the advantages of solitude.
Read the Sutta
Index to available translations: AN 6.42
But when walking along the highway, Nāgita,
I see nothing whatever in front nor behind,
it suits me,
even over the calls of nature.'
The Pali: Yasmāhaɱ Nāgita samaye addhānamaggapaṭipanno na kañci passāmi purato vā pacchato vā,|| phāsu me Nāgita tasmiɱ samaye hoti antamaso uccārapassāvakammāyā" ti.
MO: At such a time, Nāgita, as I am walking along the highway and there is no one whatsoever to be seen either ahead or behind, I am comfortable at such a time even in passing water and passing matter.
Bhk. Bodhi also mis-reads the situation:
"When, Nāgita I am traveling on a highway and do not see anyone ahead of me or behind me, even if it is for the purpose of defecating and urinating, on that occasion I am at ease.
Bhk. Thanissaro has the sense of it:
But when I am traveling along a road and see no one in front or behind me, at that time I have my ease, even when urinating and defecating.
The sutta is about the advantages of solitude over the enjoyments of gains, favors and flattery and this is about as strong a statement as can be made concerning such.
Put yourself in the position of a king, or famous person, constantly surrounded by a following, who finds himself needing to ... um ... answer the calls of nature.