During the Jindo / Hakkar fight you will be familar with the effects of phase 2 as the troll berserkers become ghosts and that all ghosts that appear around the alter of Hakkar become targetable and hostile.
There is a second side effect to this phasing, the entrance to Zul'Gurub as been removed. This means that if your group is engaging Hakkar and you are able to escape the alter area without dieing to the ghosts, you can freely explore instanced STV.
Remeber that the ghosts are slowable as well as being suspectable to a large amount of CC, however if you are a Paladin you can simply jump through the alter ghosts on the bottom floor with bubble and make it off of the island before they get you.
I'm not sure if the instanced STV is different through this method in comparison to any others however if you use this method you should also notice the poision area before the first boss has been removed of any toxins and that after leaving the ZG area you have a large tree in the middle of the road.
Happy exploring.