I’m sorry to hear that this happened! Some people are not as considerate to prey animals as others. You’ll need to start from the ground up to rebuild the trust. Rabbits are forgiving and no bond is broken forever as long as you have kind intent and food to provide.
In the future, you may want to assimilate Cupcake to louder noises. Maybe have the TV playing slightly louder for periods of time when you can console her (not blaring so she’s scared, but so she habituates to some volume of noise consistently). I watch a lot of comedic Youtube videos, where people have edited their videos to spontaneously include the loud horn sound or goat screaming. This used to jolt Wick when it started, but now he’s used to the Youtube shenanigans, haha.
Be calm and know that Cupcake will come around as long as your patient. Although it’s tempting, don’t be too aggressive with rekindling the bond. Go at Cupcake’s pace.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.