In Egypt, Israel learns that heaven exists.
At the Red Sea the Israelites discover that they can enter it and reach it.
In both cases these are relationships between heaven and earth, which unite the Divine to the human.
At Sinai I stop being interested in this relationship:
I find myself directly before God.
It is said that the Alter Rebbe was once heard to say in his prayers:
"I do not want Your paradise, I do not want Your World to Come, I want only You."
–Rabbi Adin Steinsaltz
From The Seven Lights by Rabbi Adin Steinsaltz