The 2am server douche got me too.
I agree with you in that these are personal decisions that we will all be surprised as to discover what we are capable of and what we are willing to do to survive if it comes to pass. However, even without the usual laws and the usual people enforcing them doesn't mean that for anything goes for everyone. For me there are certain lines I won't cross. I may be capable of cold blooded murder, but I am unwilling. I understand that I likely have limited survival potential because I have an internal moral code that I am compelled to live by. For me these discussions are partly about survival, and partly about figuring out where my desire to live is outweighed by what I believe is right. For me the ultimate authority is God. His will and my belief in what He has laid out as acceptable are what draw the line between what I am capable of and what I am willing to do.
I am not trying to restart to religion debates, but one's faith or whatever is the final determiner of their internal moral code is relevent to this subject.