This M.Y. answer discusses the various opinions of whether one can daven Mincha and follow it with Ma'ariv immediately afterwards when one began mincha after plag. (Note that this wasn't the subject of my question, itself, there.)
Part of the answer cites O.C. 233:1
הגה: וּלְדִידָן בִּמְדִינוֹת אֵלּוּ שֶׁנּוֹהֲגִין לְהִתְפַּלֵּל עַרְבִית מִפְּלַג הַמִּנְחָה, אֵין לוֹ לְהִתְפַּלֵּל מִנְחָה אַחַר כָּךְ; וּבְדִיעֲבַד אוֹ בִּשְׁעַת הַדַּחַק, יָצָא אִם מִתְפַּלֵּל מִנְחָה עַד הַלַּיְלָה, דְּהַיְנוּ צֵאת הַכּוֹכָבִים (בֵּית יוֹסֵף בְּשֵׁם אֹהֶל מוֹעֵד וְרַשְׁבָּ''א).
It says that in "emergency situations" if one davened Mincha after plag, and followed it immediately with Ma'ariv before tzet hokachavim, this is fine.
Would this scenario be considered "She'at Hadhcak"?
In my shul, we have trouble getting a minyan (sound all too familiar?) We prefer to daven Mincha before plag and follow it with Ma'ariv (an opinion expressed as "common practice" in O.C. paragraph mentioned). But often, we have 7 people, and the Gabbai calls or "what's-apps" (is that really a valid verb??) people to come to shul to help form the minyan. By the time we get the minyan, it is after plag, so we're following the other opinion that allows davening mincha after plag is over until night time.
Generally, in such cases, according to O.C., when one davens mincha after plag, he must wait until the stars emerge before davening Ma'ariv. However, those that came early will defect and leave the shul because the late-comers made them wait, unnecessarily.
In short, would not having a minyan for Ma'ariv qualify under the condition of She'at Hadchak, or would everyone be forced to wait until the stars emerge?