Question:
May a Baal Korei interrupt in the middle of Krias HaTorah to speak about another matter?
Answer:
Initially, a Baal Korei should not interrupt in the middle of Krias HaTorah to speak about unrelated matters. Since he is engaged in the public Torah reading, and according to some opinions is included in the blessings said by the Olah, he should continue the reading without interruption.
However, in a time of need, or if he did in fact interrupt and speak, the Krias HaTorah remains valid and the blessings are not repeated, as the main ruling follows that he is not included in the blessings of the Olah. The interruption does not invalidate the reading, and he may continue from where he left off.
Sources:
See Rav Poalim 3:42; Birchas Habayis 44:26; Rivivos Efraim 1:102; Admur in 53:13; 124:11; 282:5, 16; Igros Moshe 4:40; Piskeiy Teshuvos 139:8; 140:2 footnote 7