As reported yesterday, loan shark Rick Neelan takes Rita Sullivan captive on her wedding day next month as part of his ongoing harassment of Tina and her boyfriend Tommy Duckworth.
The twist takes place after Tina tries to get rid of Rick once and for all. Viewers will see her swipe Rick's expensive supply of drugs from Tommy and use them as leverage as she orders the villain to meet her if he ever wants to see them again.
However, when Rick does turn up at the meeting place, he has Rita (Barbara Knox) in his car and threatens to drive her into the canal unless Tina returns the gear.
Keegan, speaking to All About Soap, commented: "She's going to meet Rick, threaten him and tell him to stay out of their lives, but she hasn't thought it through, really. She's just acting on her instincts and trying to form a plan as she goes along.
"Tina's in control until she sees he's got Rita, then suddenly she feels helpless. She didn't think her plan was going to backfire like this. She doesn't know what to do next."
Asked whether Tina takes Rick's threats seriously, the actress replied: "At first no, she thinks he's all mouth. However, then she realises he's deadly serious and Tina's terrified. She tries to act like she isn't scared, but she knows what Rick's like.
"He won't stop until he gets his own way - and if that means Rita getting pushed into the canal, then he'll do it."
Coronation Street airs these scenes on Monday, June 4 on ITV1.