For your passing enjoyment are applicable selections from "The Senate Rules of Procedure for Impeachment Trials" from same in the link given further below:
118 XIX. If a Senator wishes a question to be put to a witness, or to a manager, or to counsel of the person impeached, or to offer a motion or order (except a motion to adjourn), it shall be reduced to writing, and put by the Presiding Officer. The parties or their counsel may interpose objections to witnesses answering questions propounded at the request of any Senator and the merits of any such objection may be argued by the parties or their counsel. Ruling on any such objection shall be made as provided in Rule VII. It shall not be in order for any Senator to engage in colloquy.
120 XXI. All preliminary or interlocutory questions, and all motions, shall be argued for not exceeding one hour (unless the Senate otherwise orders) on each side.
https://biotech.law.lsu.edu/blog/SMAN-104-pg177.pdf
I’ll just hazard a guess that to whom a question is directed is being told for the first time and has not received a copy nor has been told or given Morse code or smoke/flag signals of any specific question wording.