And that last panel confirms it, but if Sunny still has the key, how did Ginger get the shotgun? Sunshine can't already have looked in there sometime before all this, did she?
(as for the guess, small rectangular box...I'm going to say birth certificate, definitely some photos...maybe newspaper clippings and a letter. I was going to say written down GPS coordinates, but Breaking Bad called and said, "For real, you that dumb?")
Such a haunting page.... Look at Panel 4. "You know I'm right." 😢 And that last panel confirms i