If you want to die in style, check out this video for a tutorial on how to use the javelin to serve as a martyrdom utility!
If you succesfully do this exploit, your player should explode when being killed. This is perfect if you want to run into a group of enemies, and blow them all up!
This is considered an exploit, and if caught you can be penalized by XBox Live. It's recommended that you do not do this on a public server.
To do the glitch, you'll need to take out your javelin. Then, hold RB as if you were going to throw the Semtex, but don't throw it. Hit Y to switch to your javelin but keep holding RB. After a second release RB.