The naive and unsuspecting way the young man follows the adulteress is compared to the way three animals are unaware of the danger they are in. (See: [[rc://en/ta/man/translate/figs-simile]])
This passage implies that a hunter has trapped the deer in order to shoot it with arrows. Alternate translation: "until a hunter shoots it in its most important part" (See: [[rc://en/ta/man/translate/figs-explicit]])
This is a way of saying that this person will die as a result. Alternate translation: "it would kill him" or "he would die soon" (See: [[rc://en/ta/man/translate/figs-idiom]])