Shevet Ephraim was not actually able to successfully leave Mitzrayim early. According to midrashic tradition, a group from the tribe of Ephraim attempted to leave Egypt 30 years before the actual Exodus, but this attempt ended in tragedy14.

The story goes that some of the Ephraimites miscalculated the end of the 400 years of exile that had been prophesied to Abraham. They believed the 400 years started from the time of the prophecy itself, rather than from the birth of Isaac 30 years later4. Based on this mistaken calculation, they attempted to leave Egypt and enter Canaan on their own, 30 years before the actual time of redemption.

However, this premature attempt to leave Egypt ended disastrously. The Ephraimites encountered the Philistines of Gath and were defeated in battle15. According to some sources, as many as 300,000 Ephraimites were killed in this failed attempt7.

This tragic episode is seen as a cautionary tale about the dangers of trying to force the end of exile before its proper time. It emphasizes the importance of waiting for divine redemption rather than relying on human calculations5.

The Torah alludes to this incident when explaining why God did not lead the Israelites through Philistine territory after the Exodus:

"God did not lead them by way of the land of the Philistines, although it was nearer; for God said, 'The people may have a change of heart when they see war, and return to Egypt.'" (Exodus 13:17)

According to midrashic interpretation, this refers to the recent memory of the Ephraimites' defeat by the Philistines, which might have discouraged the Israelites if they had taken that route5.

This story highlights the importance of patience and trust in God's timing for redemption, rather than attempting to force events based on human understanding or calculations.