1)
Why does it say "they were not afraid and they did not tear"?
1.
Radak: They should have feared and torn whey they heard, and repented to Hashem.
2.
Radak citing Mo'ed Katan 26a: They should have torn their clothes. One who sees a Sefer Torah torn (Malbim - burned) bi'Zro'a 1 must tear his clothes.
1
Rashi (26a): Bi'Zro'a means that he cannot save it. Ran - it is to anger Hashem.
2)
Were all his servants not afraid?
1.
Radak: [The king and] all his officers in the house (Malbim - "ha'Omedim me'Al ha'Melech") were not concerned. However, the officers who came to the king were afraid (verse 16), and they told the king not to burn it.