After informing the UNSC about the true nature of the Key , Ruwan volunteers to " give " the Key to the Covenant . He is captured and brought aboard a Covenant ship . While the Covenant believe he is to be rescued due to a tracker embedded in him , Ruwan reveal he is actually a target . A coilgun take aim at his position and destroy the ship . Upon learning that the Key is a fake , the Brutes on Mars behead Ackerson . In a relief camp , Tyla write a song about Ruwan .