Kamui soloes all, even PS.
-Slides in PS, and slits user's neck- gg
This won't work at all. You can only injure the target if you go tangible again, Otherwise you will just phase through without doing any damage. Since, the PS is made by the target's chakra + You are surrounded by his PS Chakra, he can completely bind you with his chakra or even expel you from his PS. With his chakra restricting your movements, you will be forced to go intagible again to stop his attacks from within PS.
So, nope it's like Obito trying to warp Naruto away and at the same time dodging Gai and Kakashi's attacks. He can't go tangible and intangible both.