וַיִּסֹּ֥ב מֵֽעֲלֵיהֶ֖ם וַיֵּ֑בְךְּ וַיָּ֤שָׁב אֲלֵהֶם֙ וַיְדַבֵּ֣ר אֲלֵהֶ֔ם וַיִּקַּ֤ח מֵֽאִתָּם֙ אֶת־שִׁמְע֔וֹן וַיֶּאֱסֹ֥ר אֹת֖וֹ לְעֵינֵיהֶֽם׃
И он отвернулся от них и заплакал; и возвратился к ним, и поговорил с ними, и взял Симеона из среды их, и связал его пред глазами их.
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.