It's no surprise that Prowl was ready for her and her captive by the time she arrives at the cave. She'd let him know he was being watched before she made her move. Kagerou could have been spared easily -- all she had to have done was not let the police mech know -- though her loyalty lied elsewhere. Arcee believes in Prowl and the vision of peace he has for the colony. If he were to be outed, then that dream would never be realized.

The earth mech is thrown over her shoulder as she enters, held securely there by her arm. She only gives Prowl a brief look when he speaks to her, before she moves by him and dumps Kagerou as gently as possible. Even if he had been interfering, she didn't have to be a brute to him.

"I didn't need to sneak up on him."