Game history column "Penalties"

So I was looking at my game history this morning and I saw something that I did not understand and I am hoping that someone here can explain it to me.

I played a game of BTB and as I was going through the stats for that game I noticed a column called “Penalties” and had some people getting none myself included and others getting as many as 5. What are there penalties and how do they affect the game? Also is there a thread that explains all of the info found on your service record?

Penalties are betrayals

Suicides and betrayals count as penalties. I think each penalty counts as -1 towards the score in a slayer game.