Nobody is immune from incidents of this kind - the question is how the airline handles them. A rock bottom third world airline, and Ryanair's legal department are at great pains to point out they are not one of them, would just sack the crew involved as a warning to others. They would make no effort to discover the thought processes involved in the crew and just punish them for bringing public embarrassment to an already under-pressure airline. A professional, high-quality airline, however, would debrief the crew at length and then retrain them to proficiency. Finally they would bring the lessons learnt to the attention of all the airline's other pilots to prevent a similar incident happening again. I am sure that Ryanair will adopt that line, as they are of course a very professional airline etc, etc.
As an interesting aside, readers may be interested in the following incident which shows how it can all go pear-shaped very quickly in low visibility conditions -