The code does not make clear what the documents referred to are, however, try the following
Sub Macro1()
Const strSrc As String = "C:\Path\OpenFile.docx" 'the path of the document that is OpenFile
Dim OriDoc As Document
Dim OpenFile As Document
Dim SrcRng As Range, TgtRng As Range
'The document must already be active in order to set a selection range
Set OriDoc = ActiveDocument
If Selection.Information(wdWithInTable) = False Then
MsgBox "The cursor is not in a table cell?", vbCritical
GoTo lbl_Exit
End If
'not sure what the next line is for. Put the cursor in the cell where you want the inserted data
'Selection.Move Unit:=wdCell, Count:=1
Set TgtRng = Selection.Cells(1).Range
TgtRng.End = TgtRng.End - 1
Set OpenFile = Documents.Open(strSrc)
If OpenFile.Sections.Count < 4 Then
MsgBox "The source document doesn't have 4 sections", vbCritical
GoTo lbl_Exit
End If
Set SrcRng = OpenFile.Sections(4).Range
SrcRng.End = SrcRng.End - 1
TgtRng.FormattedText = SrcRng.FormattedText 'simply write the data to the cell
lbl_Exit:
Documents(OriDoc).Activate
Set OriDoc = Nothing
Set OpenFile = Nothing
Set SrcRng = Nothing
Set TgtRng = Nothing
Exit Sub
End Sub