There is a Unity project that allows importing models and rooms into the Unity editor. I believe it's called Alone in the Dark Model Viewer or something like that. The "texture", however, is just a palette-like bitmap file of 256 colors, similar to the one in Doom, and all model surfaces are set to one of the colors (since the AitD model surfaces are either mono-colored, noise, or fake reflection.
I'm pretty sure that AitD's PAK format has nothing to do with the one used for Quake.