The issue relates to how many sentences there are in the table cell and which sentence the selection occurs in. If the selection is in the last sentence or only sentence in the cell, the whole cell is selected. You can test for this and make the necessary adjustment e.g.
Code:
Dim orng As Object
Set orng = oWordApp.Selection.Range
If orng.Information(12) Then
If orng.Sentences(1) = orng.Cells(1).Range.Sentences.Last Then
Set orng = orng.Cells(1).Range.Sentences.Last
orng.End = orng.End - 1 'omit the table cell end character
orng.Select
Else
orng.Sentences(1).Select
End If
Else
orng.Sentences(1).Select
End If