This is an event that happened during the battle. This can be stated clearly. AT: "During the battle, Absalom happened to meet some of David's soldiers" (See: [[rc://en/ta/man/translate/figs-explicit]])
Absalom had long hair that got caught in the tree branches. AT: "his hair was caught in the tree branches" (See: [[rc://en/ta/man/translate/figs-metonymy]])
This rhetorical question means that he should have killed him. This question can be written as a statement. The phrase "strike down" means to kill. AT: "You should have struck him down to the ground!" or "You should have killed him immediately!" (See: [[rc://en/ta/man/translate/figs-rquestion]] and [[rc://en/ta/man/translate/figs-euphemism]])