You reap what you sow, and what was down was Athena.
I think panel 5 is Athena realizing that 1) she is the child of the prophecy, 2) she'd better not let Zeus know this, and maybe also 3) she does not want to fulfill this destiny and rule the madhouse that is Olympus.
At this point Athena is probably too shocked to have the thought that she might be the child of the prophecy. She probably doesn't even know if she really believes in destiny and prophecies. ^^