TARDIS doors in place of portals inspired by the recent narbacular drop portals mod.
I was inspired by the narbacular drop portals to make my own thing with TARDIS doors being stuck in the wall, if you want some sort of lore reason, you can say that the tardis blew up or something and the portal gun takes advantage of remnants of it in the timeline or whatever.
Models and textures made by me, apart from the vortex which was taken from here with permission: Steamcommunity.com