During the plague of hailstones, Paroh calls Moshe and Aharon. Shmos 9 (27).
וַיִּשְׁלַ֣ח פַּרְעֹ֗ה וַיִּקְרָא֙ לְמֹשֶׁ֣ה וּֽלְאַהֲרֹ֔ן וַיֹּ֥אמֶר אֲלֵהֶ֖ם חָטָ֣אתִי הַפָּ֑עַם ה׳ הַצַּדִּ֔יק וַאֲנִ֥י וְעַמִּ֖י הָרְשָׁעִֽים׃
Thereupon Pharaoh sent for Moses and Aaron and said to them, “I stand guilty this time. The L-RD is in the right, and I and my people are in the wrong.
He asks them 9 (28)
הַעְתִּ֙ירוּ֙ אֶל־ה׳ וְרַ֕ב מִֽהְיֹ֛ת קֹלֹ֥ת אֱלֹהִ֖ים וּבָרָ֑ד וַאֲשַׁלְּחָ֣ה אֶתְכֶ֔ם וְלֹ֥א תֹסִפ֖וּן לַעֲמֹֽד׃
Plead with the LORD that there may be an end of G-d’s thunder and of hail. I will let you go; you need stay no longer.”
We see that when he sent for them, the plague was still ongoing and continued until Moshe davenned 9 (33)
וַיֵּצֵ֨א מֹשֶׁ֜ה מֵעִ֤ם פַּרְעֹה֙ אֶת־הָעִ֔יר וַיִּפְרֹ֥שׂ כַּפָּ֖יו אֶל־ה׳ וַֽיַּחְדְּל֤וּ הַקֹּלוֹת֙ וְהַבָּרָ֔ד וּמָטָ֖ר לֹא־נִתַּ֥ךְ אָֽרְצָה׃
Leaving Pharaoh, Moses went outside the city and spread out his hands to the LORD: the thunder and the hail ceased, and no rain came pouring down upon the earth.
How were the messengers to Moshe and Aharon able to get to them through the hail?