[Looking at the average level of these arrays, they should take two days of persistent effort to crack open.]
Van scanned all of the treasures once more with his spiritual sense before landing on a desirable target. It was a pair of leather sandals with a metallic symbol on the heel. They gave off ethereal aura that caused Van's heart to beat erratically when he looked at it. These sandals were hidden behind a strong array that seemed to have been cracked slightly already.
Van guessed that a previous participant had found it and spent several days attacking the array to create that crack but unfortunately, they could not finish the job as the monster waves got too strong for them to endure. Despite the crack, this array was one of the strongest in the treasury, requiring at least ten days of continuous effort if it had been without flaws.
It was a good thing Van had the two 9th rank Ghost Guard Captains under his control!