Uh, "back" ? Do you mean they courageously ran away, right ?

rave Sir Robin ran away.
("No!")
Bravely ran away away.
("I didn't!")
When danger reared it's ugly head,
He bravely turned his tail and fled.
("no!")
Yes, brave Sir Robin turned about
("I didn't!")
And gallantly he chickened out.

****Bravely**** taking ("I never did!") to his feet,
He beat a very brave retreat.
("all lies!")
Bravest of the braaaave, Sir Robin!
("I never!")