I'm not sure if the developers have been taking PvP exploits very seriously, but I think this one is bad enough that they might pay attention. It PROBABLY applies to PvE as well, for all I know, but at any rate:

Wow. Just spent several minutes in PvP watching a guy spray an infinite, ultra-rapid-fire stream of shocking pulsar shots without ever once having to pause or reload. It was a screen-full of constant explosions with no breaks between them, trapping our entire team in our spawn room indefinitely. Could this be somehow related to shield cancelling? I don't think so, he never actually left the normal firing animation, no indication of shields being involved. He was being a striker, if that helps any investigation into how that's possible. (Wearing quicksilver helm and what looked like voltbreaker armor, though that's probably not relevant)

Oh, yeah, the times we attempted to bust out, we attacked the guy en masse... he just stood there.. SAT at one point.. not a single attack caused him any damage. Not just "not much" damage. None of them HIT even though he was sitting still and there were four people hitting him with everything we had. COuldn't be lag-related invincibility, as he had no problems getting around.

Pretty sure I'm not supposed to toss out the names of exploiters in public, but I will be more than happy to file a private report with the developers so they can ban this guy.