In the General No.6 takes a walking stick and brings it down hard on the head of the Professor as he slumbers in bed..........How did No.6 know that it was actually a modelled clay head of the Professor?
And another thing......"He's made a mess of your masterpiece," No.2 said to Madam Professor. That indicates that it was Madam Professor who actually made the modelled clay head of the Professor. So why did she scream out? Madam Professor must have known that it was not her husband lying in the bed.......ah, perhaps it was not the harm to her husband which made her scream out, but because of the damage No.6 was about to do to her masterpiece!