It happens occasionally unfortunately <img src="http://jsramsbottom.co.uk/bbs/e/icon_frown.gif" alt="Frown" width="15" height="15"><!--graemlin:-->
Good thing you feel bad, less likely to allow happen again..
BTW Not to be critical, but what kind of accuracy do you normally achieve at that range from the position you took the shot in - first shot <img src="http://jsramsbottom.co.uk/bbs/e/icon_wink.gif" alt="Wink" width="15" height="15"><!--graemlin:-->
Also, try and take em away from cover / holes etc if pos, so as you can get there quick before they get away in case anything goes wrong.
HTH - JB