In the February 11, 2019 edition of *The New Yorker*, there is a weird [profile of the writer Dan Mallory](https://www.newyorker.com/magazine/2019/02/11/a-suspense-novelists-trail-of-deceptions). Can someone help me explain the grammar of the commas I have bolded below? Why is there a comma after "disdain"? Why the comma before the words "and worked"? Presumably *The New Yorker* must have its reasons:

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> As if impatient for advancement, Mallory often used his boss’s office late at **night, and** worked on her computer. On a few occasions in 2007, after Mallory had announced that he would soon be leaving the company to take up doctoral studies at Oxford, people found plastic cups, filled with urine, in and near Linda Marrow’s office. These registered as **messages of disdain, or as territorial marking.** Mallory was suspected of responsibility but was not challenged. No similar cups were found after he quit. (Mallory, through a spokesperson, said, “I was not responsible for this.”)
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