After White had done as Dave instructed him to do by calling Tasha and telling her exactly what he wanted her to hear, Dave had immediately turned off the walkie-talkie so Tasha wouldn't be able to contact them back. This was to make her curious and long to find out what was going on, especially since the message had mentioned Dave's name.
"Alright, I've done as you said. I called Tasha and delivered your message, so release me now," White said, glancing up at Dave.
"Right. I guess you've done your part then," Dave said, keeping the walkie-talkie in his pocket. "But unfortunately, I won't be able to release you."
"What?!" White shouted. "You despicable liar! I should have never believed you in the first place!" White said.
"Don't take this the wrong way, doctor, I'm merely avenging the deaths of those you killed," Dave said.