And the world shall be turned back to primeval silence for seven days, as it was at the first beginnings: These seven days of the end time recall the seven days of creation. For the primeval silence, compare 2 Esd 6.39. Primeval means “original” and “ancient.” We may render this sentence as “Then the world will become completely silent as it was in the beginning, and it will be this way for seven days.”

So that no one shall be left may be translated “As a result, no one will remain alive.”

Good News Bible provides a helpful model for this verse.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Esdras. (UBS Helps for Translators). Miami: UBS, 2019. For this and other handbooks for translators see here.