TempDB Query Top 4 (SQL)

(@P1 numeric(10),@P2 numeric(10))INSERT INTO #tt84 WITH(TABLOCK) (_REFFIELDRRef) SELECT
T1._IDRRef
FROM dbo._Reference42 T1
WHERE ((T1._Fld595 = @P1)) AND (T1._ParentIDRRef IN
(SELECT
T2._Q_001_F_000RRef AS Q_001_F_000RRef
FROM #tt80 T2 WITH(NOLOCK)))
UNION SELECT
T3._IDRRef
FROM dbo._Reference42 T3
WHERE ((T3._Fld595 = @P2)) AND (T3._IDRRef IN
(SELECT
T4._Q_001_F_000RRef AS Q_001_F_000RRef
FROM #tt80 T4 WITH(NOLOCK)))