Archimedes, who does not seem to be interested in what is going on, on the other side, wants to be playful. The idea of leaving/disowning was being explained Marcus in this stage of the plot.
Explanation:
Siege of Syracuse led to loss of independence of Greek cities in Italy and Sicily. Archimedes was on of the defenders of Syracuse, who tried to help with certain calculations and quotations that were needed for war against Romans.
In this siege, Archimedes worked along with the King who requested him to calculate few specific aspects that can lead to a strategy of attack against Romans. After a while, when Romans continuously proved victorious in every move they faced, Syracuse's King had to surrender.
Meanwhile, Marcus(one of the defenders) instructs every one to disembark. He explains the reason clearly that their loss is evident now. Archimedes who is still involved playing mathematical games and calculations, Marcus explains to him that disembarking is the only way left for them to survive.
Ignoring this, Archimedes continues his playful games. The disembarking, later proves to be true as Archimedes dies in the war.