Incomplete question. The excerpt read;
The Call of the Wild.
A hundred yards ahead the path turned and sloped steeply into the main street. It would have required an experienced man to keep the top-heavy sled upright, and Hal was not such a man. As they swung on the turn the sled went over, spilling half its load through the loose lashings. The dogs never stopped. . . . They were angry because of the ill-treatment they had received and the unjust load. Buck was raging. He broke into a run, the team following his lead.
Answer:
the real reason why the dogs continue to run after the sled turns over
Step-by-step explanation:
We note from this excerpt that "the dogs...were angry because of the ill-treatment they had received and the unjust load," also because Hal lacked the experience to keep the sled upright.
Therefore, if Hal had narrated the events he would be unaware of the real reason why the dogs continue to run after the sled turns over; which was because they were angry at him.