Red Bull failed to boxes

During the past Monaco Grand Prix, saw a situation of those this season are not regular: Red Bull failed in one of his pit-stop, or rather two, and both Sebastian Vettel and Mark Webber lost important unemployed seconds.
In the case of Sebastian Vettel, the lost time was little contrary to his partner. Even so, the German lost time due to the confusion that still not stole the victory. A mechanic look at tyre and seems that he wondered if the set of tyres is really for Vettel as the German would have to be mounted superblandos tires instead of the soft which allowed him to reach the red flag.
For its part, Webber, was called to boxes in the same back to Vettel, causing chaos and confusion. When the Australian boxes mechanics are that they have still not have available the tires to install leaving the Australian stopped for several seconds. Even in those times people don't know that do or where to turn.
The head of Webber to move from side to side says almost everything. As much as the mechanic that after the two pit-stops to look at the sky and wondered the why (imagine that the why send stop to the two pilots at the same time). And having done so, why were not the two sets of tyres ready?