"You tell me when he is here. I will check the goods. Once I find everything satisfactory, I will give you what I promised. As for what will happen after that, that won't be any of my business. If you lose the medicine, then you are gone. I have exhausted the medicine on your family," Calista said to him, completely unaware of what was going on in Orson's mind.
Because of the condition of the girls, she was forced to take out the last bottle. Because she couldn't dilute it, the medicine's level had reached a dangerous level. And now, with the medicine she promised to give Orson, it meant that the remaining medicine wouldn't be hers as well.
So, if an accident were to happen along the way, even if she was cut into a million pieces, the medicine would be no more. At least the kind that would treat their mysterious illness. The medicine for some lesser ailments, she has some, but not for giving to that family.