But why would you want to send the image to PS with none of your Adjustments from the RAW processor applied? It makes no sense. Remember that once you have sent the image to PS it is no longer a RAW image, it HAS to be converted to an RGB raster image (even if it has yet to get the actual RGB file created) in order for PS to be able to work on the file. It doesn't really matter which RAW processing program you use they all work pretty much the same way in this regard. First you apply all of your basic processing to the RAW file. Things like Colour (White) Balance, exposure and white/black point correction, curves corrections and the other similar tools. Depending on your RAW processing program you may also do some hue/saturation/luminance corrections then add Noise Reduction and at least some input sharpening. Of course many modern RAW processors now also allow you to add in local corrections with brushes etc, as well as a certain amount of basic cloning work such as spot healing. All of this is done as parametric adjustments to the RAW file and are only applied to the image when it is exported from the RAW processor as an RGB Raster Image. At the point of export the you cease to be working with RAW data and are now working with a standard three colour per pixel image of whatever bit depth you have chosen for your export.
Now when specifically speaking about LR, when you call the Edit in Process what happens is that Photoshop is opened, and so is Adobe Camera Raw although you do not actually see the ACR interface. LR passes both the list of edits that it holds in it's database to ACR and ACR then generates a bitmap image in Photoshop in exactly the same way it would do if you had done the same edits in ACR and then opened it to Photoshop from ACR. So if you are adding no additional editing to the image (or creating a VC that is reset to default) then you simply get a bitmap (raster) image with only the default processing applied. Then when you hit save in Photoshop it then creates the chosen file type according to your preferences and imports it into the LR Catalogue next to the original RAW file.
If you are then trying to add back the corrections you made to the original RAW file to this RGB raster image you will get worse results than exporting it with the corrections, as you are no longer working with the original RAW data.
Alan