LUKE 22:62

 And he went outside and wept bitterly. - Luke 22:62

Wasn't he already outside?  They were making a fire.  Or did he go outside of the temple - place that was called the Court of the Gentiles?  So, when Peter goes outside he is actually going to where the Gentiles would stand, those that "weren't part of the family."  

I'm not sure if he did this on purpose, or if he just wanted to get away from everyone (including Jesus), but it is ironic that he denies Jesus three times and then goes to the Court of the Gentiles.

I guess we all feel like we belong there sometimes.  I know that I do a ton of stuff that makes me feel like I am not "part of the family."  The cool thing is that Jesus doesn't let him stay there - metaphorically.  He brings him back in, and the rest is literally history.