Armor blocking syringes

[poland spring]

This sounds like a smart enough idea, to be honest. Makes a Doctor's job harder but it makes sense as to why.

Emergency auto-injectors should always work, though. Let's just say they can penetrate the armour better!

For that matter things should have bleed resistance, I mean some armor reduces bashing and burn damage, so why not the only other external type of damage? 

And I always imagined the auto injectors to work like https://youtu.be/JKQ-BpO4Gzo?t=1m28s