Back to topic:
I have found a video on youtube that shows a bit more.
The video is 22 minutes long, obviously professional, released two years ago, with only 18(!) views so far. So I highly asume nobody here knows it.
https://youtu.be/DVaIv9Su51s
At 19:00 there is an interview with Prost, before the podium ceremony. At 20:00 Prost and Senna are brought to the ceremony.
The whole video is mute, but my assumption is, they let Senna join the ceremony as some kind of compensation for missing his first win so close.