Has there been an emergency situation you have handled? How about a very urgent problem you have solved? Or, what about that time you had to drop everything to get something done at the last minute for someone else? These will all make sufficient examples for this question. Simply share your situation with a high-level overview. The interviewer is truly interested in how you reacted! Next, share how you worked through the situation including what steps you took and the final outcome. Be sure to mention that you did not allow the situation to ruin your day, and you simply did what needed to be done!