Just having a little look on youtube and came across this. I suspect I may have seen it before but think it's worth taking another look...
http://www.youtube.com/watch?v=5v3KKPYq ... re=relatedFirstly they look SO uncomfortable with this line of questioning.
Secondly I reckon Kate dobs them in it by saying that 'we don't actually know if there was any of Madeleine's blood in the apartment'. Presumably this means that they cannot then later explain away any of her blood, unless they suddenly remember a nose bleed or whatever
Thirdly - they do all they can to NOT answer the actual questions!