It’s just like English, some people use wide variation in tone to add emphasis or drama to whatever they’re saying. (I’m sure there’s a linguistic term for that but IDK what it is.) You could say the same thing in a completely flat tone and it wouldn’t change the technical meaning.

According to the Koreans in my house, her accent isn’t awesome, but it's not as bad as Rick Yune’s in Die Another Day and Olympus Has Fallen. That guy sets the bar for terrible Korean.

Korean’s not tonal.