Done? Good. Let us begin . . .
Take pretty much anything, from lung cancer to diabetes and from firearms to plumbing, and the portrayal of it can be either done well or poorly. Stephen King wrote in his book On Writing that if you have a great knowledge about plumbing and love science fiction, how about writing from the POV of a plumber in space? Interesting concept, for sure.
Now, one can write very rudimentary and broad about a given topic, but when it comes to specifics, please get your facts right. In firearms, Glocks do not have safeties like other handguns (they are in the trigger) and there is no hammer to cock back. I have nearly stopped reading books because of an error like this. It's annoying!
How about diabetes? Trust me, I have more knowledge about it than I know what to do with. But with my children, living with it day-after-day, they know more than me.
One of my daughters recently read a book where the main character had type 1 diabetes (T1D) and the author got it completely wrong! Not only wrong, it was so wrong on so many levels that a simple Google search would fix many of the problems the author had.
I am currently writing a short story where the main character is a nuclear engineer on a spaceship. I know virtually nothing about being a nuclear engineer, or being on a spaceship for that matter, but I'll gloss over what I need and that's it.
It's all about the story anyway.
But if you're writing about someone with diabetes and if their blood sugars are in the 70's, it's probably not the end of the world. If it was in the 20's, yeah, that's an emergency and nothing else matters for the diabetic. Also, when it comes to diabetes pumps, again, please get the facts right. They're not all the same and each has their little . . . quirks.