PPD form 3 question 51

The question asks about cleaning exterior brick on a historic restoration project in a cold windy climate. One of the answers suggests using a cleaning method using liquid chemicals, answer is incorrect due to using liquids in a cold climate can lead to freeze thaw which can damage the brick. Instead the correct answer is to use low pressure water and detergent, how is that any better? Seems like you are still applying liquid which can lead to freeze/thaw damage.