If you work out the years of Yaakov's life, there are fourteen years unaccounted for. Tradition tells us that between Parshas Toldos and Vayeitzei Yaakov spent fourteen years hiding out in yeshiva (cf. Rashi at the end of Toldos citing Megillah 17a).
This is difficult on several levels. Firstly, wouldn't that be the first place Eisav would look? Secondly, long ago Yaakov was described as יושב אוהלים, "one who dwells in tents." Rashi explains, "the tent of Shem and the tent of Ever." Yaakov was always in yeshiva, and now he goes there to hide?! What did he do, change his seat? Thirdly, when Rivka was having a difficult pregnancy, she went לדרוש את השם to find out what was going on. Rashi explains that she asked Shem, which means the Yeshiva was in her neighborhood! (In her condition, she could not have traveled far.) So Yaakov hid from Eisav for fourteen years in a yeshiva down the block? The very same yeshiva he had been learning in his whole life?!
I believe the answer can be found in the Gemorah itself. The Gemorah does not say Yaakov went to hide in the Yeshiva of Shem. Nor does the Gemorah say he went to the Yeshiva of Shem & Ever. The Gemorah says Yaakov went to hide in בית עבר. (See מהרש"א מגילה שם.)
There were two different Yeshivos! Shem had a Yeshiva and Ever had a Yeshiva. This is indicated by the very first reference - יושב אהלים - "tents." "The tent of Shem and the tent of Ever." The Midrash is unequivocal: "[Yaakov] left the Beis Medrash of Shem and went to the Beis Medrash of Ever" (Tanchuma Yashan, Vayishlach 9).
There was never "one big Jewish tent." There were always (at least) two different tents.
Yaakov spent his entire life studying under his master, the Alter Zeide Shem. The Midrash says he served Shem for fifty years. When Shem passed away thirteen years earlier, Yaakov undoubtedly became the Rosh Yeshiva of Beis Shem. But now he had to hide. Where to run? To the last place Eisav would expect him to be. As a rank-and-file student in the competing, second-tier Yeshiva, the Yeshiva of Ever, Shem's great-grandson.
It never occurred to Eisav that Yaakov would go to Ever, for Eisav's arrogant mind could never understand the humility that Torah study engenders. But it was this humility that saved Yaakov's life, broadened his outlook by exposing him to a different דרך הלימוד, and - מעשה אבות סימן לבנים - became the hallmark of the true בן ישיבה.
