1)
Why does it mention here that Avshalom fled? Verses 37-38 discuss this!
1.
Malbim: Because David was anxious to know what happened to the other Bnei ha'Melech, he did not think to send to chase and catch Avshalom, and he was able to flee.
2)
Who were the "Am Rav"?
1.
Radak: They are Bnei ha'Melech.
3)
What is "mi'Derech Acharav"?
1.
Radak: It is from the other side of the mountain, from the side of the mountain. The suffix Vov in Acharav refers to the mountain, even though the verse mentions the mountain after this, just like "va'Tir'ehu Es ha'Yeled" (Shemos 2:6).
