You must right-click on ICARUS.v1.2.23.103516.part01.rar and select "Extract Here" . WinRAR will automatically pull the data from part03 when it needs it.
Because the data is linked, you cannot easily extract a single file from the middle of the archive without WinRAR processing everything before it. ICARUS.v1.2.23.103516.part03.rar
Are you seeing an during extraction, or were you just checking if the file is safe to open? You must right-click on ICARUS