The chest opener is one of the scarier physical tools within surgery... "ca-RACK-k-k-k-KK"
As for "chance of being hacked apart," anybody can donate their cadaver to science — most facilities require prior enrollment and will recover the corpse, nationwide.
You might end up sold into scientific experimentation... if you're morbidly obese (e.g.) you won't be used for student anatomy (if you care).
Not my cup of tea, personally, but my ultimate point is you might get used in something you disagree with. Look into the history of cell lines used in medicine for some of the controversy and perpetual pain for surviving family members, as an example.
This 2022 LessWrong post mentions a $60 5-hour option at the Sf Bay Area's Merritt College (in Oakland):
https://www.lesswrong.com/posts/5PBWgHiCiiJHjPRSn/what-it-s-...