Answer: this metaphor could mean 2 things depending on what this text is about: (#1) this could refer to the characters inner thoughts that they are brave like a lion and that they did the right thing and then by calling them a rat it could suggest that they instead did the wrong thing
(#2) The character wants to think of themselves highly, and they compare themselves to a lion to convey this because lions are considered brave, strong, and powerful. Then the metaphor of comparing the character to a rat is used to show the reader the reality. This character doesn’t have the good qualities that they believe they have and so they are compared to a rat because rats are the prey of lions and possess opposite characteristics.
