Betty: Beep! Beep!

This is one of those cases where the comic would be better if the third panel were omitted, but actually omitting the third panel would probably render the joke incomprehensible to anyone who doesn't read the comics section every day. It's not the cartoonist's fault, so much as it a flaw in the medium. Daily exposition is a necessary component of even the very simple continuing stories in comic strips because cartoonists just can't trust their readers to stay up to date or pay a ton of attention. It doesn't have to be this way, of course, but it is the way the medium has evolved at the present time.