Responsibility for a mess-up

I was evaluated today on my performance with a standardized patient where I had the "not so fun" prospect of telling a practice patient "bad news". In addition to it being bad news was included in the scenario that my practice had dropped the ball and not told the patient about a possible cancerous lesion on their lungs from 4 months ago. How to explain that? and the emotions you feel about it were kind of tough? Its all a part of the process..

cheers

Greg