You simply CAN'T gag a person with a 3-4 inch strip of duct tape over the mouth. It is EXTREMELY easy to scrunch your face a few times to unstick even the strongest duct tape. You would have to wrap the tape completely around the head to prevent screaming. (And even then it wouldn't be guaranteed.) This is not the first movie to make this mistake, by any means, but it is one of the worst offenders since the tape is barely long enough to cover the corners of her mouth. She could have had that off enough to scream in less than 5 seconds.