Why does it say "va'Yetzei ha'Mal'ach"?
Radak: After the angel showed the Megilah to him, he disappeared from him. Afterwards, he came out and showed the Eifah to him.
Malbim: He wanted to show to him a different matter. They have other sins for which they will be punished like the measure of their sin - unlike false oaths, for which the punishment is unlimited. The angel went out to another level to show to him...
Why did he tell him to lift his eyes and see?
Rashi: He should see something else that will go out of Kodesh ha'Kodoshim.
Radak (3): He did not see what was written in it, like Yechezkel, until the angel told him, for the power of Nevu'ah was fading. Therefore, Zecharyah's visions are unclear; Nevu'ah ceased with Chagai, Zecharyah and Malachi.
What do we learn from "ha'Yotzeis"?
Radak #1: It leaves Beis Hashem, like the first matter [the Megilah].
Radak #2: It leaves Eretz Yisrael.
Radak citing Targum Yonasan: These revealed matters.