The following will probably do the trick.
Code:
Sub ShrinkCellTextToFit()
Dim orng As Range
Dim i As Long
Const iCol As Integer = 2 'the column to process
If Not Selection.Information(wdWithInTable) Then
MsgBox "Put the cursor in the table and try again"
GoTo lbl_Exit
End If
For i = 1 To Selection.Tables(1).Rows.Count
Set orng = Selection.Tables(1).Cell(i, iCol).Range
orng.End = orng.End - 1
Do Until orng.ComputeStatistics(wdStatisticLines) = 1
orng.Font.Shrink
Loop
Next i
lbl_Exit:
Exit Sub
End Sub