Hermione briefly contemplated her situation. She realized she would be in deep trouble if the Polyjuice potion wore off, or if Antonin realized that she was an imposter. As she looked him in the eye, she also realized he was completely infatuated with her, more like Bellatrix and he would probably do anything for her.
"I really don't have time for this," Hermione insisted. "The dark lord left something of value in the vault and I simply must get it." At first, she had no trouble maintaining eye contact as every word she spoke was true. She just neglected to mention that the only reason she wanted to find it was to destroy it. Then she looked down at a bear skin rug on the floor.
"If there is anything I can do to help you."
"Just get me back to Gringotts. Now," Hermione commanded.
"Don't you want to get your id first?"
"I…" She paused her speech. "Seem to have misplaced it."
"Are you sure about that?"
"Take me back to Gringotts now." Hermione pointed her wand at him and raised her voice. "We don't have time for that."
"How's two minutes work for you?" Antonin asked calmly, as he slid open a hidden compartment within one of the logs that made up the walls of this cabin. Then he presented Bellatrix's id to Hermione.
Hermione's eyes opened wide in genuine surprise. "Thank you!" Then she bit her lip realizing yet again she said something Bellatrix would never say.
"I will consider a thank you from you as a major victory," Antonin smiled at her. "I am just happy that you are pleased."
"How did you get this?" Hermione asked.
"Ah!" Antonin looked down at the bear skin rug as though that had an answer for him, but it didn't. He firmly believed that if he told her the truth about that she would never believe it. She would call him a liar, or worse. She would probably target him with an unforgivable curse, but he didn't particularly care to speculate which one. Then he looked up as his eyes met hers. "I thought we didn't have time for that."
Hermione knew in an instant he was hiding something, but right now that didn't matter, especially with that time crunch looming over her. Harry and Ron were probably worried sick about her, so she needed to get back to them. Great kisser or not, she didn't have time for a Death Eater who fancied Bellatrix LeStrange. "You are right. Let's go. There will be plenty of time to talk later." She had no intention of making good on that promise.
He used the port key again and took them very near the bank. Where Hermione had trouble walking in high heels, she leaned on Antonin as they both walked in. He smiled with pride, all too happy to be her escort. In his own mind, he had the sexiest woman alive on his arms.
Fortunately, very little time had passed. Much to Hermione's relief Ron was still here in his Death Eater disguise and Harry was probably also still here under his invisibility cloak. She was certain of it when she heard faint whispers between the two of them arguing about what to do next, try to find and rescue Hermione, or use an imperious curse and force the teller to take them to the vault.
The whispering stopped once Ron and Harry noticed Antonin and Bellatrix. They felt no such relief from this. It was possible Antonin killed Hermione and showed up with the real Bellatrix, or Hermione somehow managed to persuade the Death Eater to bring her back here. Harry planned to follow them to the vault, and Ron would only go if 'Bellatrix' requested it, something the real Bellatrix was unlikely to do.
Hermione spoke in an overly loud voice, so Harry and Ron would know to shut up. "I got the ID you wanted. Just take us to the vault already," she nearly shouted at the goblin bank teller.
The bank teller looked over her ID. "Yes, this seems to be in order. Right this way, Ms. LeStrange," the bank teller said.
Hermione turned around and looked at Ron. "Are you coming," she asked him.
Sure enough, Hermione, Harry, Ron and Antonin all went to Bellatrix's vault.