。
She read the situation at a glance.
Literal
She [topic-は] that-place [genitive-の] situation [object-を] one-eye [with-で] saw-and-grasped.
見て取る is a compound verb fusing 見る ('see') with 取る ('take, grasp'), semantically 'to see-and-grasp' — to perceive something instantly and completely. 一目で ('at a glance,' lit. 'with one eye-look') sets the speed: not just understanding the situation, but understanding it immediately. 情勢 is a slightly heavier word than 状況 — 'circumstances' with a connotation of strategic or political dynamics. The phrasing reads like a description of a sharp, perceptive person sizing up a room without a wasted moment.