What is the meaning of "k'Hinav'i"?
Radak: While I was prophesizing.
Why did he fall on his face and scream over Pelatyahu's death? Yechezkel saw that he is a Rasha!
Radak: He died suddenly, and he was one of the leaders of the nation. Perhaps he would have repented!
Malbim: Initially, he thought that "they will fall to the sword" (10) refers to the 25 men who bowed to the sun, but not to the Klal of Yehudah. Now that he saw Pelatyahu die before the enemy conquered Yerushalayim, he realized that the Nevu'ah was for the nation.
Why did he say "Kalah Atah Oseh"?
Radak: This is a question, even though there is no prefix Hei. We find like this ? "Erdof Acharei ha'Gedud ha'Zeh" (Shmuel I, 30:8), "Atah Zeh Bni Esav" (Bereishis 27:24) and similar verses.
Malbim: You decreed death on the residents of Yerushalayim, who are the only remnant of all of Yisrael,