The actress quit the ITV soap in 2008 when Jo decided to escape from abusive husband Andy (Kelvin Fletcher).
"It was a real honour for me that my character was chosen for that storyline," she told This Is Bristol. "It was the first time that they had explored domestic abuse in such a big way.
"It was a really smart decision to choose Jo because it gave out the message that this can happen to a young, feisty girl. It's not always silent, timid characters that this happens to."
She continued: "It really is an actor's dream to get a story like that. It was a slow burner, which went on for two years. It had to be - you couldn't have them happy one minute and Andy lashing out the next. I lived and breathed that storyline."
Pallet added that Jo could one day arrive back in the village.
"I think it was the right time for my character to leave and it was a positive ending - she left Andy and moved on," she said. "Plus nobody knows where Jo has gone - she wasn't killed off so there is always a chance of her return."
> Pallett: 'Casualty role similar to Jo'