Lev got the job at the Magnus Archives because he wanted to pay his rent.
He'd been adjuncting for three years. He'd barely managed to afford a studio when he was splitting it with Asher. Affording it on his own meant googling a lot of things like "is peanut butter and ramen a complete diet?" and "cheapest vitamins."
(He doesn't return his parents' phone calls. He knows what they're going to say. He knows he's a failure.)
Working at the Magnus Archives for a year wouldn't exactly look good on his curriculum vitae.He was not entirely thrilled about studying the paranormal, seeing as it was nonexistent. But he had to admit he'd probably never get a tenure track position regardless; he was brilliant, but a lot of people were brilliant. And they'd let him do research. And he'd be able to buy a pair of shoes that didn't have holes in them and see movies in theaters and maybe even take someone out on a date when he was ready, which he isn't, but someday he might.
At some point, all you want out of a job is not having to eat ramen anymore.
So he goes to his first day at work.