TT #704 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:07
And if the man does not desire to take his yevamah, then his yevamah shall go up to the gate to the elders and say: “My husband’s brother refuses to establish a name for his brother in Israel; he will not perform the duty of a husband’s brother for me.”
Torah Temimah points to Yevamot / Rava.
TT lemma: הַשַּׁעְרָה.
אָמַר רָבָא: צְרִיכִי דַּיָּינֵי לְמִקְבַּע דּוּכְתָּא, דִּכְתִיב וְעָלְתָה יְבִמְתּוֹ הַשַּׁעְרָה אֶל הַזְּקֵנִים.
English: Rava said: The judges must designate a fixed place, for it is written “then his yevamah shall go up to the gate to the elders.”
On the daf / in context: A designated location serves the purpose of publicizing that she is a chalutzah and therefore forbidden to a kohen.
Derash requiring a designated place for the ceremony.
Chalitzah should be performed in a fixed, public location designated by the court (preferably at the outset; after the fact other forms of publicity may suffice).