And I looked, and behold: See the comments on 2Esdras 11.2. Here this expression may be rendered “As I watched” or “While I was watching” (Good News Bible).

The eagle flew with his wings, to reign over the earth and over those who dwell in it: In verse 1 the eagle came up out of the sea; in verse 2 it stretched its wings over all the earth; here it begins to fly. The phrase with his wings may be left implied in many languages (so Good News Bible), since eagles always fly with wings.

Here is a possible model for this verse:

• As I watched, the eagle began to fly [or, rose/soared into the air], and began to rule over the whole world and everyone in it.

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.