Vincy

Try shifting the upper the hinges slightly higher and away from the existing location since the screw holes are loose.Suggest you change to new hinges and longer screws.

The wall is made up of block and it s a non-structural element thus can be demolished. However, you will have to re-do your water-proofing as the "tanking system" will be damaged as the water-proofing membrance 100mm up-turn onto the said wall will be gone inadditional the the area where the supposed wall to be demolished are not water tight as well.

The rust could have been caused by chemical such as acid wash for tiles during the washing by the contractor.