Halo 5: Guardians teaser announces Sunday countdown

It seems like in less than 24 hours we’ll have additional information about what’s coming on Halo 5: Guardians. A YouTube video was posted on a Tumblr account called Hunt The Truth along with a countdown that will end on Sunday at 9 PM Eastern time. What will it be? Why is there a bullet with the word “traitor” written on it, hitting a Spartan helmet?

https://www.youtube.com/watch?v=V9D2HzbT9Pc

[Source]: Hunt The Truth / Tumblr.