Betrayed our 4-man squad after ARC Titan fight

We spent 20 minutes fighting an ARC Titan in Dam Battlegrounds. DarkViper was in our squad, helped the whole time. The SECOND the Titan dropped its loot, he opened fire on all 3 of us while we were low on health and ammo. Took everything. He even typed "gg ez" in chat. This was clearly premeditated — he was saving ammo during the Titan fight while we burned through ours. Absolute scum behavior. Has multiple reports on his Embark ID already.