138. Talking During Torah Reading

23:7 If the baal korei is called for an aliyah, another person should stand next to him. The Torah was given to us through an intermediary (Moshe), so our interactions with the Torah should likewise involve the use of an intermediary. (Our practice is for someone to stand on each side of the bimah so that there are at least three people present during the reading of the Torah – the one reading and a person on either side of him - Mishnah Brurah 141:16.)

23:8 The congregation is not permitted to talk while the Torah is being read, not even about matters of Torah study. (The need to be silent begins once the Torah has been opened to recite the blessings over it – Mishnah Brurah 146:4.)This is true even between aliyos. (There may be room to be lenient regarding Torah study between aliyos – MB 146:6.) One may not leave the shul while the Torah is being read (even if he already heard the Torah and even if there’s still a minyan without him - MB 146:1). One may, however, exit in-between aliyos if necessary.