He asks Joby to imagine being responsible for the men marching together as one army.
Explanation:
"... like a wave on the ocean shore." He tells him to understand that he is very important. ..."the drummer boy at Owl Creek..." " One day he will be known as the Drummer Boy of Shiloh.
HI! So this sentence is symbolizing a broken heart after a fight with this girls boyfriend, It just means her heart was broken like glass without use of similie.
