He turned the mouse over, inspecting her for any kind of gemstone over her body, but found none. That would make things easier. They sometimes crystalized for him, which would absolutely get in the way here.
He arranged the mouse on her back, who at this point had stopped moving entirely, besides breathing, from the sheer amount of mold-like fungus across her skin. He traced along her body with one of his claws, pressing down here and there, feeling squishy organs beneath him, before at last beginning to cut.
It was...messy, unfortunately. His claw went too deep, raggedly cutting open the chest and belly of the mouse with his heavy 'hand'. He grit his teeth in frustration. Damn, he needed to get better at this. "Sorry, Aati," he swiftly apologized as the mouse gave a high-pitched squeak before falling still.
Well, that was too bad. But it was okay that she'd died in the beginning stages - it didn't ruin everything.
Once she was open, he began carefully digging around, extracting each and every bit of her and laying it across the ground. A claw carefully pointed through everything, identifying organs, wondering over their purpose. He didn't understand the body, not completely, but he could identify the heart - he'd accidentally opened it in his messy dissection and blood was spilling rapidly from it. It had pumped one or two more times before stopping.
He could also identify the lungs. They'd inflated and deflated rapidly when he'd opened her, but now were still. How strange they were and amazing as well! What was the purpose, anyways, of breathing? What did it do for oneself?
The stomach he quickly discovered when he cut it open, revealing half-digested bugs and tough grasses. Another might have been repulsed at the mess he'd made on his floor, but Anubis didn't mind, much. It was just science, after all.
The rest of the organs, he wasn't sure. A long, stringy piece, a short piece, little stone-like organs, and a deep red slab. He marveled at them, wishing he could have seen them in action, but there would be other opportunities in the future.