If one started a meal right before shkiah or during bein hashmoshis what should they do? My question is prompted from the halacha that one may not eat before praying Maariv. However with that said I do know of a caveat where one says Shema and appoints a shomer to pray Maariv later. But in this scenario does he have to stop his meal at Tzeis HaKochavim (which is presumably when the time for saying Shema begins) and appoint a shomer? Of course all of this applies where one has prayed mincha already.
There's a prohibition to start a meal (k'beitza) 30 minutes before the reading of the shema in the evening (Shhulchan Aruch Orach Chaim 235:2).
In this case, one who started a meal during this time, may continue his meal so long as he reads the shema at tzet and prays later (if there's time left to pray; otherwise he prays immediately). See seif below:
אָסוּר לְהַתְחִיל לֶאֱכֹל חֲצִי שָׁעָה סָמוּךְ לִזְמַן קְרִיאַת שְׁמַע שֶׁל עַרְבִית, וְאִם הִתְחִיל לֶאֱכֹל אַחַר שֶׁהִגִּיעַ זְמַנָּהּ, מַפְסִיק וְקוֹרֵא קְרִיאַת שְׁמַע בְּלֹא בִּרְכוֹתֶיהָ וְגוֹמֵר סְעוּדָתוֹ, וְאַחַר כָּךְ קוֹרֵא אוֹתָהּ בְּבִרְכוֹתֶיהָ וּמִתְפַּלֵּל. הגה: אֲבָל אֵין צָרִיךְ לְהַפְסִיק לִתְפִלָּה, הוֹאִיל וְהִתְחִיל לֶאֱכֹל; אֲבָל אִם לֹא הִתְחִיל לֶאֱכֹל אַף עַל פִּי שֶׁנּוֹטֵל יָדָיו, צָרִיךְ לְהַפְסִיק (ר''ן פ''ק דְּשַׁבָּת); וְאִם אֵין שְׁהוּת לְהִתְפַּלֵּל, מַפְסִיק אַף לִתְפִלָּה (הָרַאֲבָ''ד בְּהַגָּהוֹת פ''ב מֵהִלְכוֹת ק''ש).
The reason for this gezerah (Berachot 4b) is because Chazal prohibited certain acts like eating and sleeping that may prevent the recitation since one is bound to eat, be satisfied, and sleep all night; thus missing the mitzvah.
even on shabbos, you're allowed to continue eating if you started before shekiah. the same should apply during the week - if you started before shekiah, you can finish your meal. if you started during bein hashemashos you would seemingly need to stop, unless you appoint a shomer or daven later anyway, as sabbahillel said. it sounds logical that you would need to pause your meal to appoint a shomer right away so you don't forget, but i don't see why you would need to stop.
@Double AA - sounds like he's talking about shekiah on shabbos afternoon.