Biblical verse Nu12-04 states
And the Lord spoke suddenly to Moses, and to Aaron, and to Miriam, Come out you three to the Tent of Meeting. And the three came out.
However verses Nu12-06:08 identify
prophecy not as a physical voice in the real world
but rather as a voice speaking within the prophet
-- the prophet hears internally.
And he said, Hear now my words; If there is a prophet among you, I the Lord will make myself known to him in a vision, and will
speak in him in a dream.
Not so with my servant Moses, for he is the trusted one in all my house.
With him I speak in him mouth to mouth, manifestly, and not in dark speech; and he behold the form of the Lord. Why then were you not afraid to speak against my servant Moses?
Hence the Rashi:
Each of the 3--Moses, Aaron, Miryam--heard within them,
at the same time, a command from God for all 3 of them
to assemble at the tent of meeting.
Rashi literally says The 3 of them heard the voice
at one time. It would not be possible physically [using ordinary
voice] to communicate simultaneously to 3 people in different
locations.. We have clarified Rashi's explanation by
citing Nu12-04:06 which emphasizes that prophetic communication
happens within the person. This emphasis explains why Rashi
had to clarify that the simultaneity could not have happened
with ordindary voice.
We have classified this Rashi as a Spreadsheet Rashi.
The verse says God spoke to the 3 of them and Rashi explains
that God spoke to the 3 of them. Rashi does not address any
issues of meaning, grammar, style,contradiction or alignment.
Rather Rashi is explaining the physical process by which simultaneous
communication can take place. Thus Rashi is simply clarifying
physically how something took place. Any Rashi clarifying
how is classified by us as a Spreadsheet Rashi. Typically
Rashi will give geometric diagrams. However in this verse, Rashi
explains how physically.