As soon as they landed, the red haze opened up wide, encompassing a large area the ancient magic determined safe from discovery. There were a few trees, some stony out-croppings for cover, but most of the area was ground thick with grass and weeds.
According to the most ancient magics, the red mist would only dissipate when Harry, as the challenger, felt he had satisfaction or was dead. Harry didn't intend to take this that far, but the danger was real enough, even if they were protected from prying eyes.