After all, a window was clearly part of the Ark's structure, as we see from:
צֹ֣הַר׀ תַּעֲשֶׂ֣ה לַתֵּבָ֗ה וְאֶל־אַמָּה֙ תְּכַלֶ֣נָּה מִלְמַ֔עְלָה וּפֶ֥תַח הַתֵּבָ֖ה בְּצִדָּ֣הּ תָּשִׂ֑ים תַּחְתִּיִּ֛ם שְׁנִיִּ֥ם וּשְׁלִשִׁ֖ים תַּֽעֲשֶֽׂהָ׃
A light shalt thou make to the ark, and to a cubit shalt thou finish it upward; and the door of the ark shalt thou set in the side thereof; with lower, second, and third stories shalt thou make it.
רש"י על בראשית ו, טז 1 צהר. יש אומרים חלון, ויש אומרים אבן טובה המאירה להם:
(According to one opinion, the צֹ֣הַר means a window...)
And further from:
וַֽיְהִ֕י מִקֵּ֖ץ אַרְבָּעִ֣ים י֑וֹם וַיִּפְתַּ֣ח נֹ֔חַ אֶת־חַלּ֥וֹן הַתֵּבָ֖ה אֲשֶׁ֥ר עָשָֽׂה׃
And it came to pass at the end of forty days, that Noah opened the window of the ark which he had made.
Even after Noach's dispatching of the dove, Noach apparently was completely sure that the land was dry, as we see from:
וַֽ֠יְהִי בְּאַחַ֨ת וְשֵׁשׁ־מֵא֜וֹת שָׁנָ֗ה בָּֽרִאשׁוֹן֙ בְּאֶחָ֣ד לַחֹ֔דֶשׁ חָֽרְב֥וּ הַמַּ֖יִם מֵעַ֣ל הָאָ֑רֶץ וַיָּ֤סַר נֹ֙חַ֙ אֶת־מִכְסֵ֣ה הַתֵּבָ֔ה וַיַּ֕רְא וְהִנֵּ֥ה חָֽרְב֖וּ פְּנֵ֥י הָֽאֲדָמָֽה׃
And it came to pass in the six hundred and first year, in the first month, the first day of the month, the waters were dried up from off the earth; and Noah removed the covering of the ark, and looked, and behold, the face of the ground was dried.
Noach only ruled that it was safe to venture out upon seeing the dry land, so, again, why not just peek out of the window? (I fear I'm missing something basic here, but this very much troubled me during my shnayim mikra this week.)