Although Lumian's target was clear, he didn't immediately attack Hisoka's dream projection. This was because his opponent was still beside the black ancient tomb, and under the gaze of three items with godhood power, Lumian might be targeted by all of them if he teleported over.
The three items hadn't reached the point where Lumian couldn't be under their gaze simultaneously, and they appeared to last only a few minutes. However, they displayed certain humanoid characteristics, as if they possessed the ability to think and make decisions on their own. If targeted by them, it would be no different from facing weakened Sequence 4 demigods.
