In the twinkle of an an eye Joan was arrested and taken to one of the cells. She tried to resist but decided against it as she decided she will wait till she sees Lucas. She didn't want to make things difficult for Lucas when he finally regains consciousness.
As she was being taken away she saw Lady Kerry and Queen Tacha having a discussion which shew knew will definitely be a plot against her. That was her initial source of concern till she also remembered Lucas.
The last time she saw him he was still unconscious with Lorenzo standing by his side. If he was conscious or not now she couldn't tell but she had hopes Lucas would be coming for her soon.
Her cell was kept isolated from every other political prisoner hence she didn't get to see anyone in the cell.
She was left isolated and frustrated till the early hours of the next day when she picked the footsteps of someone else inside the cell for the first time.