David from the Lost Boys?

Okay well in the movie at about one hour eight minutes, just after Marko was killed, David is chasing after Sam, Edgar and Alan. After David burns his hand, and the three boys escape, I notice the camera closes up on his face and a single tear falls from his eye. I don't understand this part at all and I get the feeling that this tells us something very important about David? Is his eye watering? Is he crying because..? Could someone please explain this to me.