They had not seen the experiment, yet they knew the results.
Macbeth has been adapted so many times for the same reason why all Shakespeare's plays have been adapted so many times. It is because they are not bound to a single point in time and by changing temporal details it can be applicable to any society at any time. The theme that is "power corrupts" has been ever present and this is why it keeps getting adapted.
The mood was furious but then it got back calm and steady
The answer to this passage is a: youthful energy of life