Genesis 39:12

that she caught him by his garment, saying, Lie with me: and he left his garment in her hand, and went forth into the street.

AND HE LEFT HIS GARMENT IN HER HAND. Out of respect for his mistress he did not wish to take the garment from her hand with his superior strength, and he removed it from upon himself, as it was a garment which one wears as a robe and headdress. But when she saw that he left his garment in her hands she feared lest he expose her to the people of the household or his master, and so she preceded him to them, saying that he had removed his garment to lie with her, but “when he saw that I screamed he fled in confusion.” This is the meaning of the verse, And it came to pass, when she saw that he had left his garment in her hand. This is also why she did not say, “And he left his garment in my hand,” but she instead told the men of her house and her husband, And he left his garment ‘etzli’ (with me). (with me) indicates that he himself had removed his garment, as explained above.

וינס, from the room in question,

ויצא החוצה, once he had left the room she was in, he walked slowly with his usual gait so as not to arouse curiosity when he would be observed as fleeing. He did not want to have to answer all kinds of questions that would embarrass him or Mrs Potiphar. She, however, having only seen that he fled from the room, was alarmed that he might answer questions directed at him by incriminating her. Therefore,

ותתפשהו בבגדו, “she grabbed him by his outer garment.” According to Kohelet Rabbah on Kohelet 7,26, where the author describes a woman’s hands as having been artificially restrained, אסורים, the kind of woman described by Solomon there would grab men in the street and try and seduce them. Even the relatively chaste women are described there as aggressive in that respect. During the 12 months that Joseph was in Potiphar’s house, he was exposed to those tactics by Potiphar’s wife on a daily basis. When the Torah speaks of these ongoing attempts at seduction (verse 10) as occurring יום יום, “every day,” this must be considered as if Joseph had withstood a year’s temptation. The word is used as meaning “year” as in Esther 3,7. He would literally have to take evasive action, such as covering his face, practically shrinking to the ground. She would use instruments in order to force him to resume his normal posture. She would use the argument that she was not really married to Potiphar; he was a homosexual and had never consummated the “marriage.” He had to explain to her that the Hebrews were not allowed to have sexual relations with Egyptian women even if the latter were unmarried. She would threaten him with having him consigned to jail. Joseph would reply that his G–d had means of freeing him from jail. She would threaten to have him blinded, to which he replied that his G–d could make the blind see. Eventually, if it had not been for the priests who testified hat the drops of semen she produced as evidence that he had tried to rape her were in fact not from a human being, he might have been sentenced to death. This eventually became the reason why he dealt so extraordinarily generously with the Egyptian priests during the years of the famine. (Tanchuma, section 8)

וינס ויוצא החוצה, “he fled, leaving the house.” As a reward for Joseph’s fleeing the presence of his master’s wife on that occasion, G–d told him that He would reward him when the sea of reeds fled at the approach of Joseph’s coffin when the Israelites were facing the sea with the Egyptians threatening them from behind. (Tanchuma on parshat Nasso, section 30, interprets Psalms: 114,3: הים ראה וינוס, “the sea saw and fled” as meaning just that.)