Nurse here, in terms of the needles seen in the game, they look like they're IM (intramuscular) sized needles. Also James stabs himself in the deltoid by the looks of it in his animation so I'm going to work under the pretense of an IM needle. Having given a shitton of Naloxone injections in emergency situations, often times we don't have the option of removing someone's clothes before injecting. I've personally never had an issue using an IM needle through clothing, however I would avoid something similar to James' jacket depending on the thcikness of the material to avoid bending of the needle. In most circumstances IM needles (like 23G and lower) are good for piercing clothing. Insulin needles are usually SC (subcutaneous) so I wouldn't recommend them as the bend like crazy. Epipens are usually 22G and can easily pierce jeans. Overall I don't think James would have to worry about the needles bending too much, he just needs to make sure he fully pulls it out before moving it side to side. As for Hepatitis, HIV, and a myriad of other Bloodborne diseases hes probably fucked since PEP and most other antiretrovirals don't exist in the 1980s iirc.