Barnabas decides he doesn't want to find out just yet if he's still impervious to (lead) bullets, so he hangs up the phone. But he still refuses to let Lang harm Jeff, who now is wearing a white shirt.
The following exchange answers some questions in earlier ep. discussions. It also sums up Julia's character to a T:
Barnabas swears Julia won't do anything to jeopardize the experiment because, as he tells Lang with modestly lowered eyes, Julia cares for me. Unfortunate, but she does. I knew that already, Lang replies, but Julia is too inquisitive. She will pry and pry until she finds out everything. I think we should go ahead and just tell her everything, Barnabas insists. Her feelings for me will make her even more trustworthy.
Yes, Barnabas is still a user, but he still wants to save Jeff's life--for Vicki's sake.
Julia is horrified at Jeff's tale of Lang's doings. But she really shouldn't be after spending all this time with the Collinses! She goes to the lab to see for herself. She uncovers the patchwork, still-headless body and screams hysterically, despite all the horrors that she has already seen--and in some of which she has participated. The two men rush upstairs. Lang tries to tell her what a wonderful experiment it will be. Julia is horrified that Barnabas still wants to go through with it. You’re mad! she exclaims to Lang. Some might say so, Lang answers with grandiose unconcern.
Julia agrees to Lang's proposal of "just one more death"--for Barnabas's sake, but then she changes her mind. She leaves behind her handbag--a sign of her extreme agitation--when she locks herself in the study and utters possibly the very best closing line in an episode!