I thought you couldn't attach body parts that aren't cut clean (as opposed to sawing)

Yeeeeeah, realism ruined, dropping this xD

Yes and no, but this saw they used wasn’t sharp enough so it did a ton of damage to the nerves so yeah the author needs to do a bit of research

This is a common misconception.

When a body part is severed in a way other than a clean cut the part goes through various processes. Surgeons will attempt to clean as well as repair tissue, tendon, bones and veins to assist with reatachment to parts that have been crushed, mangled or less clean severs. It all comes down to the damage to the over all finger. So there are a lot of factors that are involved.

Now the aforemention of a quack doctor. I doubt this would have been a success. XD