Very likely this breeder was more of the backyard variety and thus gave you a rat with bad temperament. No breeder in their right mind would sell you a single rat.
i got 3 rats and i’ve had them for several months now, two from petco and one from a breeder, the two from petco were as skittish as you’d expect a rat to be, just hiding and running, now they’ll run up my arm when i put it in the cage, the one from the breeder, however, was FAST moving skittish, like my brain couldn’t comprehend how fast he moved when i got somewhat close at all, seemed like he teleported, now he’s doing better and will come up to me but won’t associate with my hands, he also jump-startles HARD when any sound is made or i make any sound at them like a quiet click noise from my mouth, he’s still a very scared fella and i suppose it’s only been 4 or so months which is pretty early but my control group of rats is just so vastly different
Very likely this breeder was more of the backyard variety and thus gave you a rat with bad temperament. No breeder in their right mind would sell you a single rat.