Why is Torah Called "Toras Moshe"? The Mishpatim Question

The shiur opens with a fundamental question: why is the Torah (תורה) called "Toras Moshe" when Moshe received it from Hashem (ה׳) rather than authoring it himself? A Midrash Tanchuma on Parshas Mishpatim offers an intriguing answer by distinguishing between two acts of mesirus nefesh. The Midrash explains that Parshas Mishpatim is called on Moshe's name because of his mesirus nefesh for dinim—specifically, the act of killing the Egyptian taskmaster to save a Jew. Later, the Torah as a whole is called "Toras Moshe" because of his mesirus nefesh during the forty days and nights on Har Sinai when he went without food or drink. Rabbi Zweig raises a fundamental difficulty: if the entire Torah was given through Moshe with mesirus nefesh, why does Mishpatim require a separate explanation? Why isn't the mesirus nefesh of Kabbalas HaTorah sufficient to explain why all of Torah—including Mishpatim—is called on his name? The Midrash seems to imply that Mishpatim has a unique status that requires its own act of mesirus nefesh distinct from the rest of Torah, but the reason for this distinction is unclear.