Injection sites (BSD Chapter 97 Spoiler)
Disclaimer: All of the medical information below is merely from the Internet so it maybe false information. I am not absolutely certain about what I found. I might edit this post when I have collected more necessary information.
Heavily inspired by this post by @tortolette
From what I gather, Dazai and Fyodor were injecting poison at 72-90 degree-angle, which might be subcutaneous or intramuscular injections and not intradermal injections or intravenous injections.
To quote from Drugs.com:
Intramuscular (IM) injections. IM injections are given deep into a muscle where the medication is then absorbed quickly by surrounding blood vessels.
Subcutaneous (SC) injections. SC injections are injected into the innermost layer of the skin called the subcutis or hypodermis, which is made up of a network of fat and collagen cells. SC injections are also known as ‘subcut’ or ‘SQ’ injections. These injections work more slowly than an IV or IM injection because the area does not have such a rich blood supply.
"Intravenous (IV) injections. An IV injection is the fastest way to inject a medication and involves using a syringe to inject a medication directly into a vein. When people talk about receiving medication via IV, however, they are usually talking about an IV infusion or drip, which involves using a pump or gravity to infuse the medication into a vein, rather than a syringe. IV infusions allow a set amount of medication to be administered in a controlled manner over a period of time.
Intradermal (ID) injections. ID injections are given directly into the middle layer of the skin called the dermis. This type of injection is absorbed more slowly again than IV, IM or SC injections."
"Muscle", "Subcutaneous tissue", "Vein", "Dermis", "Epidermis"
According to Children's Hospital of the King's Daughters, "the most common areas for subcutaneous injections are:
the upper outer area of the arm
the front and outer sides of the thighs
the abdomen, except for a 2 inch area around the navel
the upper outer area of the buttocks
because these are away from joints, nerves and large blood vessels."
According to Healthline, "intramuscular injections are absorbed faster than subcutaneous injections... Common intramuscular injection sites are:
Deltoid muscle of the arm. The deltoid muscle is the site most typically used for vaccines.
Vastus lateralis muscle of the thigh.
Ventrogluteal muscle of the hip.
Dorsogluteal muscles of the buttocks."
In short, here is the difference between the two:
However, in this panel, Dazai and Fyodor did not inject the poison in the mentioned sites:
Let’s say Dazai and Fyodor intentionally gave IM injections angularly instead of a 90 degree in the wrong sites, this is what’s meant to happen according to Jesse Kesler from Quora+:
He said: "You may reduce the effectiveness of the vaccine." I guess Dazai and Fyodor did that so they can lengthen the amount of time they have before the poison takes effect.
Also, I wondered why they had chose the 90-degree angle instead of the others, and I found this: According to Journal of the American Academy of Dermatology, there is “no difference in pain between 45- and 90-degree angles of injection, but that the energy required to inject was lower with insertion at 90 degrees. Lower injection energy may lead to less tissue distension and thus less pain. In addition, 90-degree angle insertion may result in less direct transection of nerve endings than 45-degree angle insertion.”
As I don't know whether they chose intramuscular injections (which allows the poison to be absorbed quickly) or subcutaneous injections (which works more slowly than an IV or IM injections), I cannot reach a conclusion whether they chose less pain over more time to survive.
There are three more analyses that I know, I will put the links here if you want to continue reading about this subject.
1. This one by @tortolette
2. This one by @infjsnightmare
3. This one (about the poison) by @overtainted
I apologise in advance for any inaccuracies and please feel free to correct me in the comment section. Thank you for reading my ramblings :'>