A. B. and C. - S1-E3
Corrected entry: When he breaks into the secret lab, Number 6 finds the syringe and substitutes plain tap water for the drug to be used on him. But even a small injection of unpurified, non-saline water can cause severe pain and is potentially lethal: it can cause oxygen bubbles to form in the bloodstream, and if this air embolism reaches the heart, cardiac arrest can result. Certainly not a risk Number 6 would take. (See http://en.wikipedia.org/wiki/Air_embolism.)
Corrected entry: The sticking plaster on No. 6's forehead is firstly on the left side of his head but then changes sides in following scene. Finally, it goes back to the original position.
Correction: Simply wrong. It is always on the right side. It appears to be on the left side in one scene, but that is because we are seeing a reflection in a mirror.
Corrected entry: During the opening credits, when he has resigned, a typewriter is seen to repeatedly put a letter onto the platen. In the next shot, a series of Xs are placed over the Prisoner's picture. The key that is repeatedly pressed is H. (The X key would have come from somewhere near the left of the picture of the keys, not the middle.).
Correction: Although it is suggested, it is never confirmed that the key is typing out the x's across the card. There are dozens of 3's and other letters and numbers all over the card, and there may even be some on the other side. The point is, we can't tell what the H key is typing because we never see both in action and the letter being typed at the same time (plus, there's been quick cutting throughout the intro, so it is possible it appears here as well).
Corrected entry: Everyone in the Village is supposed to have a number instead of a name. Yet, Tom Cobb, the ex-agent Number 6 recognizes in the medical ward, is for some reason an exception. Number 2, the doctor, Number 4 and Number 6 himself all call the man Cobb.
Correction: Numbers are used to conceal prisoners' identities. Number 6 recognises Cobb from the outside world, after which there's no point in anybody calling him anything else.
Correction: In order to produce a dangerous embolism, between 300 and 500 ml of air needs to be injected. That is way beyond the capacity of the small syringe we see. And Number 6 would be confident that, like all medical professionals, the lab technician would expel any air from the syringe before the injection. It's a bog standard medical procedure.