Define "mistake": error, misadventure,or accident?
ACCIDENT: you bumped into the person starting the IV in the ambluance as it was driving on bumps and somehow this caused a death. You might hear about how you should have been secured and stayed away from the IV-sticker, but as long as you followed procedure, probably ok. Any adverse action, especially death, can spark a lawsuit.
ERROR: The IV starter says "Pass me the yellow capped vial" and you get the blue one, but not on purpose and it's a fatal drug. If it was OK for you to be passing the vial, but you failed to follow standard safeguards, you could be fired and negligence charged against you. Probably no criminal liability, but civil and license repercussions are possible.
MISADVENTURE: Despite your level of training, you say "I've seen this a hundred times", try to start the IV yourself (six times before success) and push the blue topped vial. If you willfully exceed your level of preparation, or willfully violate safety measures, even if you think you are in the right, that is potentially criminally, civilly and professionally actionable.
In any event, if there's a death involved, your employer will probably terminate you to distance themselves from the event because to keep you implies acceptance implies culpability.
As an EMT? Toss up between us leaving the scalpel behind at the childbirth scene (no sequel), our pinching the CVA patient's upper arm skin in the ambulance litter when it was lowered (no sequel), and giving my driver/partner wrong directions to an address (nothing bad happened, but sure could have).
