Here, the employer wants to know how you might deal with an unexpected situation. Unforeseen things do happen on the job, and sometimes they are not within our areas of responsibility or expertise. They are also exploring if you are a team player. Tell your interviewer that if the situation warranted, you would notify a supervisor or the person responsible, particularly in an emergency or critical situation that something needed attention. Explain and clarify that you would assess the situation, and if correcting the problem was within your capabilities and not in violation of protocols, that you would step up and do what needed to be done, and then report it. Mention that you understand your own work would usually take priority, but that you would assist in any way you could, either hands-on or redirecting other personnel to see that the situation was properly resolved.