This is what Urk said during the live stream with DoD.
http://planetdestiny.com/another-vault-glass-chest/
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chest 1: trials of kabr chest 2: Templar's well chest 3 & 4: gorgon's labrynth and you get stuff when you beat each "checkpoint", say like when you beat the Templar, you get something (asides from the chest). unless you got balls as big as the traveler, you can check other parts of the gorgon's labrynth, but I think there is only 4, and only in the places I stated.