Carl has already allowed himself to be tempted by his son Riley's girlfriend Mercedes Fisher (Jennifer Metcalfe), and fans will see the pair get passionate once again in the soap's 3,000th episode tomorrow evening.
However, in an episode due to air next week, Carl's wife Heidi (Kim Tiddy) has a nasty accident in the kitchen - causing him to rethink his recent behaviour.
Opacic told Inside Soap: "Carl's getting jiggy with Mercedes when Heidi burns her chest badly. She's been cooking a meal to welcome Mercedes into the family as Riley's partner. Heidi has to go to hospital and Carl feels incredibly guilty.
"The situation brings it home to them that what they're doing is wrong. Carl and Mercedes feel really guilty about what's happened. But we'll have to wait and see whether they can stay away from each other."
Opacic added that Carl will remain dead-set on opposing Riley and Mercedes's relationship - especially after he hears they are engaged.
He said: "It's everything Carl's been trying to stop. Riley wants to demonstrate to Mercedes that she's the girl of his dreams. But Carl is determined to prove to his son that Mercedes isn't good enough for him."
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