What do we learn from "va'Yetzei ha'Echad me'Iti"?
Malbim: When Yosef left me, there was not so much danger, for three reasons. (a) He was "ha'Echad" (the first to leave) - my Mazal had not yet become bad. (b) He did not go 'me'Im Panai' (far away), rather, "me'Iti" (nearby). (c) Refer to 44:28:152:3.
Ha'amek Davar: The more praiseworthy of the two [left me].
Why does it say "Ach"?
Ohr ha'Chayim #1: This hints that Yosef is only slightly 'torn' - he is not afflicted with slavery or incarceration.
Ohr ha'Chayim #2: This excludes only Tereifah, but "Chayah Ra'ah Achalas'hu" (37:33) was fulfilled via the wife of Potifar. Yosef was destined to father 12 'Shevatim,' but Aveiros caused him to lose 10 of them; due to her [seduction], 10 drops of semen exuded [from his fingertips - Sotah 36b].
Malbim: There was no other danger [except for a wild animal] on the path he took.
Ha'amek Davar: He did not die normally; rather, he was torn.
What is the significance of "v'Lo Re'isiv Ad Henah"?
Ohr ha'Chayim: This implies that he is in the world, just I have not yet seen him [after he left me].