Did Obama/Holder Really Grant Immunity?

A reader walks me through an argument that I considered, dismissed, and am now forced to consider again:
Here's what Attorney General Holder said today in his statement: "Holder also stressed that intelligence community officials who acted reasonably and relied in good faith on authoritative legal advice from the Justice Department that their conduct was lawful, and conformed their conduct to that advice, would not face federal prosecutions for that conduct."
Note the emphasis,
So -- doesn't that mean that if there were IC officials who did NOT act reasonably, did NOT act in good faith, and IGNORED the OLC's advice -- that if evidence were to come out that some folks did this -- that they could be subject to prosecution?
My reader notes, quite correctly, that the memorandums are themselves careful to stress that their grant of legality is not universal; if and only if the interrogators and officials followed the appropriate guidelines would the conduct be legal. And there is plenty of evidence in the public record about interrogations that did not follow these guidelines.
My reader:
In theory, at least, prosecutions could proceed against any operative who deviated from these memos. It could also proceed against any operative who was holding the memos up as a sham defense. If the operative were not convinced of the applicability of the memo to his actions, but proceeded anyway, that would be a bad faith reliance on the memos. And prosecutions could proceed against anyone who, despite the memos, acted unreasonably - perhaps the letter of the memo would allow continuing an abusive interrogation, but any reasonable person could see that continuing to torture would kill the detainee - that might still be prosecuted.