。
She fainted and fell to the floor.
Literal
She [topic-は] consciousness [object-を] lost [and-て] floor [on-に] fell.
気を失う is the canonical idiom for fainting — 'to lose one's 気,' which is to lose consciousness. The verb 失う ('to lose') in its abstract sense pairs naturally with intangibles: 自信を失う ('lose confidence'), 意識を失う ('lose consciousness' — a near-synonym), 視力を失う ('lose one's eyesight'). The te-form chains the fainting directly into the falling, with に on 床 marking the destination of the falling motion.