shzl400's friend said:

Michael and hillsideresident have already answered this, but another way of putting it is to think of a series of votes in successive weeks, with candidates successivey eliminated (as, for example, in the French presidential election), which is what AV seeks (more or less) to replicate synchronically. If there were three candidates in an extended ballot of this sort, it would hardly make sense to eliminate the candidate who came second in the first vote and let the voters who had voted for him or her in the first round vote in the second round for the candidates who had come first or third in the first round, would it? Surely the bottom candidate has to be eliminated first.