I thought it was going to be messed up Vaughn before episode 4, now I'm pretty sure it's not. We got 2 hints about him. He says he lost people he cared about. Vaughn didn't really lose anyone. Unless he means Rhys, like methaphoricaly.
And the Conference call is in Jack's office. It could've been just a different one, but it was probably there for a reason. So I'm guessing it's someone who is at Helios.
"the only thing sucks in ck2 is my daughter sister on the me dick" - Cackman