What would you do in a particular situation?

I found myself writing this after witnessing the Boston Bombing where people in complete knowledge that their lives were in danger, raced to help those already hurt by this tragedy and it got me going what would you do in a certain situation. I wrote about his a few days ago and still I want to find out how you would react in particular situation. Take for example a bombing, even if you think that you been hurt. Would you help the one who is more hurt than you or just wait to get yourself help? Would you risk your limb to save some animal or waste your time to fetch something for some old folk even if you are in a rush? Would you help a blind person or a person with other disability to cross a road or intersection if you can? Would you have an eye contact with somebody who is in need of help or just ignore them and go about your business and how it will burden or haunt your conscience later on? It really takes a selfish person to do deeds which separate them from others. It depends on your nature, your upbringing and how you want to be perceived by others and society. And how about his for the ultimate sacrifice that would you die for some stranger or your family member if it comes to that. I know it is very insensitive (and I apologize for that in advance) but have you ever thought about. I hope that nothing similar ever happens to you but this is an unpredictable world and anything is possible.