hmmm it was an intresting read however I have a question

If someone is eavesdropping, they introduce errors into the communications," Pearson says. "If that happens we just throw the keys away and start over
now both ends need to know the key right? (that is the transmitter and the reciver) and im assuming there is a finite amount of keys, and if the system moves to a new key if its being evesdropped then isnt it possible for the network to run out of keys? I mean sure more could be transmitted but if someone was still evesdropping the line from what i gather the reciving end wouldnt get them and even if they did then the evesdropper would now have the key so wouldnt a second secure method of transmition be required?

anyone who understands this topic better than me could you please clarify/correct me here, also if what im saying is correct could a second quantumly encrypted line be used aswell, so if one line gets tapped then new keys are transmitted on the second line and then the first line switchs over to the newly transmitted keys?

also if there wasnt another way (which im sure the probably is) would it be possible to DOS a network by just evesdropping it untill it ran out of keys?