You may have been fiddling with a setting and were in preview mode (with the K-3 for white balance, as its the only mode where this could happen). IE, you wanted to check white balance, so were on the preview screen, in which case hitting the shutter will give you a preview of what you want to shoot, but won't actually fire and record without an extra step involved.
My guess here is probably user error (I've done the same before, but usually only for a shot or two) If you were in "shoot, move to next stone, shoot, next stone" mode, I could easily see pulling a D'OH and doing what you're describing.
Last edited by Sagitta; 06-03-2015 at 10:40 AM.