Maybe I can provide some insight here. I have a friend who is a level 50 Scoundrel and was one of the first 50s on the server. We work together and play together so I know the in's and outs of his class pretty well.
Essentially, there are several factors which make this burst insane. The "Ambush" which is the big hit around 7k is around 2.5k base damage. My friend is a Biochem, so he will blow a trinket, Biochem reusable Surge adrenal (15 seconds of +450 surge), a trinket of +220 crit/surge, and an ability that gives his next attack 50% armor penetration. With all that and talents the ambush has a near guaranteed chance to crit.
Even more gross is that these cooldowns continue after the initial ambush, which is why it is chased by 2-3 strong attacks and can usually kill people.
I'm not saying that any of this is OK, but perhaps you will have a bit more clear of a picture as to what is going on now.