What did ancient Oriental kings do to people who failed to fulfill their demands?
They were ruthless: when someone could not fulfill the king's demand, the penalty was death. Nebuchadnezzar, enraged because his magicians could not recover his dream, commanded all the wise men of Babylon to be destroyed, and the decree went out that they should be slain.
Les explains that ancient Oriental kings were ruthless, and if somebody could not fulfill what they asked him to fulfill, they would put him to death. In chapter 2, Nebuchadnezzar was shaken by a tremendous dream and demanded that his magicians not only interpret it but also tell him what the dream was. When they could not recover the dream, he became angry and very furious. The king commanded to destroy all the wise men of Babylon, and the decree went forth that the wise men should be slain. That included Daniel and his fellows, so Daniel speaks up in verse 14.