They play musical chairs once I'm on that pedestal
Before one is hung he is usually standing on a chair or pedestal. In the game of musical chairs everyone fights for a chair, and after each round a chair is removed. When Kendrick say “they play musical chairs once I’m on that pedestal” he means once the government has had enough of him, or whoever disagrees with his views, he will be tied to a rope by his neck, and the chair/pedestal he is on will be removed.
Also the KKK were known for lynching African Americans who tried to express their views, or the ones who were in the government.
Musical chairs is a game where everybody tries to find a seat to sit down in before the music ends (there are fewer chairs than people). Whoever is left without a chair loses. Kendrick is saying that once he gets on the pedestal to speak, people begin scrambling for seats so they can listen.
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