We disagree on the yo. I think if he was frantic and yelling at her she wouldn’t have kept her focus.
I could see that if it was rope but not duct tape. I think that would be harder to make it look like you were still bound but really weren’t.
You can slip out of duct tape while it still remaining in tact. You wouldn't have to cut or tear it. Depending on her body position, she could have simply kept her hands behind her back, but was noticed was she started dialing, which would necessitate moving her arms noticeably.