Mohawk Lane, off Stag Lane, off of Stanwich, has rarely commanded anything close to $6 million: under-$2 is more usual. There was a sale in the $5s on the street four years ago: No. 26, for $5.2 million in 2013, but that was a purchase from owners who had foolishly paid $7.5 million for it as "new" construction in 2008 (it had sat on the market since 2006). And it was traditional, rather than bunker-contemporary. My guess is that the $5.2 final price seemed like a bargain because the buyers' agent let her clients be confused by that 2008 price: that was dumb, and they'll probably regret paying so much when they go to resell.
Just as both buyers of 26 Mohawk might have been better served by their respective agents to dodge a falling knife, I'd be inclined to recommend waiting a bit on this one.