I was playing tennis two weeks ago. And when I was volleying, the ball was deflected from my racket and it hit the guy who was picking up the ball between the courts. He was playing tennis in the adjacent court. He was wearing glasses and got a tiny cut in the nose and blood bruise in the white part of his right eye like http://www.flickr.com/photos/mcwillimedia/3711406801/ . Looks like they call it 'Subconjunctival hemorrhage'. The glasses were okay. I told him that I am sorry it happened and gave him some first-aid stuff. Apparently, he went to the ER after the incident and contacted me today. He e-mailed me that he wants to know if I can pay the part of his ER copay. If it is just ER copay, I am willing to pay but I am worried. I am concerned that if I pay something to him, I would admit the responsibility and open the door for another series of bills. What do I have to do? BTW, he is the college professor.