水をかけると、意識を取り戻した

when [someone] splashed water on [someone], [they] regained consciousness

→ 水
phrase Rare #41,837
when [someone] splashed water on [someone], [they] regained consciousness 水をかけると means “when/as soon as someone splashed or poured water on someone,” while 意識を取り戻した means “regained consciousness.” The subjects are understood from context.
JA: その女の子は気を失ったが、私達が彼女の顔に水をかけると、意識を取り戻した。
EN: The girl had fainted, but when we splashed water on her face, she regained consciousness.

その少年は私達が彼の顔に水をかけると、意識を取り戻した

The boy regained consciousness when we splashed water on his face.

その女の子は気を失ったが私達が彼女の顔に水をかけると、意識を取り戻した

The girl fainted, but she regained consciousness when we splashed water on her face.

その少年は気を失ったが我々が彼の顔に水をかけると、意識を取り戻した

The boy fainted, but he regained consciousness when we splashed water on his face.

その少女は我々が彼女の顔に水をかけると、意識を取り戻した

The girl regained consciousness when we splashed water on her face.