Mischief Rule vs Purposive Approach

Hi there, I'm a bit confused between the Mischief Rule and the Purposive Approach. In one of your lectures, 'Gardiner v Sevenoaks' was used to explain the Mischief Rule, but Kaplan places the same case under the Purposive Approach. Could you please explain which aspect of this case makes it an example of the Mischief Rule and which aspect makes it an example of the Purposive Approach? A different example for each, or a simple key identifier to distinguish them in the exam, would also be really helpful.