One marco plus one marco doesn't make two Marcos but ONE WHOLE MARCO.

MARCO!!!! ...Oh I geuss the other half is dead since there was no Polo.

Eren: Hey, Jean!!!
Jean: What do you want, Eren?
Eren: Guess who I found this morning.
Jean: Who?
Eren: Marco.
Jean: Really?!?! Where!?!?
Eren: At a half off sale.*smiles evily*
Jean: Oh go screw yourself,Eren.

Jean: MARCO!!!
Marco: .......
Jean: *waits a second before calling out* Marco!!!!!!
Marco: ...............
* Eren appears behind Jean*
Eren: Get over it Jean. He is gone!!!!
"Ghost": POLO........
Eren: °o° * runs away like a chicken*
Ymir: Oh so worth it.

Sad and Ironic
Marco sitting in the corner listening to Half a Heart by One Direction

Even more Sad and Ironic
Marco lip-sing to Half a Heart by One Direction and is happy.

What the Aot/SnK cast would say at Marco's send off:
Eren: I only knew one half of him and the other I can't say.
Jean: It feels like he had half a chance at love.
Levi: Heh. Not my problem.
Armin: Only if he got to live the other half of his life and be whole.