Possible Clues:

• Purgative
• Releasing pent-up emotions
• Medicine found by little girl on a lorry
• Member of old heretical sect finds time in charge is a relief
• Catch it off artist throwing up inside - how is that an emotional relief?
• Catherine and Arthur I see, said it's very cleansing
• So purgative, as girl goes to far north to get rid of a cold
• Cleansing, purifying
• Woman briefly jumps on lorry, releasing emotion
• Having two beastly types in charge can be purgative