Carpenter's kick came at the end of a 65-yard, seven-play drive over the final 1:32 and capped a rally that saw the Dolphins score 17 fourth-quarter points, halting a three-game losing streak.
Ryan Tannehill compiled 253 aerial yards with a touchdown while Reggie Bush and Daniel Thomas combined for 147 rushing yards with a score for Miami (5-6).
The Seahawks (6-5) got a 21-of-27, 224-yard performance with two TDs from Russell Wilson, but it wasn't enough as Seattle's two-game winning streak came to an end.
The Seahawks lost for the fifth time in six road games.
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