וַיִּסֹּ֥ב מֵֽעֲלֵיהֶ֖ם וַיֵּ֑בְךְּ וַיָּ֤שָׁב אֲלֵהֶם֙ וַיְדַבֵּ֣ר אֲלֵהֶ֔ם וַיִּקַּ֤ח מֵֽאִתָּם֙ אֶת־שִׁמְע֔וֹן וַיֶּאֱסֹ֥ר אֹת֖וֹ לְעֵינֵיהֶֽם׃
Und er wandte sich von ihnen ab und weinte, dann ging er wieder zu ihnen und redete mit ihnen; darauf nahm er den Simon aus ihrer Mitte und ließ ihn vor ihren Augen binden.
Rashi on Genesis
ויסב מעליהם AND HE TURNED AWAY FROM THEM — He moved some distance away from them so that they should not see him weeping.
Rashbam on Genesis
את שמעון. In order to separate him from Levi, so that the two between them would not hatch a plot to cause major damage as they had done in Shechem at the time.