It seems it could be interpreted both ways at this point, but I was wondering if anyone has encountered any strong evidence I haven’t.
Here's the order of the relevant events as presented in the episode:
- Obi-Wan's briefing; Obi-Wan tells Ahsoka to capture Maul to learn more about Sidious
- The briefing is interrupted by Rex, saying there's been an attack
- Ahsoka and Rex leave the briefing to meet Sterling, who tells them about Jesse being captured by Maul
- Maul interrogates Jesse and tells Gar Saxon to kill Almec
- Ahsoka, Rex, and Bo-Katan meet Almec in prison to ask what Maul knows about Sidious
- Gar Saxon shoots Almec
Each of the Ahsoka scenes follows from the previous scene, so they must take place in chronological order.
According to the Canon reference book Star Wars: Timelines, Almec's death happens before Anakin goes to the opera, which happens before Obi-Wan travels to Utapau. These events are shown as taking place in consecutive order:
- Code of silence: On Maul's command, Saxon shoots Almec before Ahsoka can finish questioning him, then makes his getaway.
- Maul orders his underlings to go into hiding.
- A Jedi's temptation: At Coruscant's Galaxies Opera House, Palpatine plays on Anakin's doubt and anger about the Jedi's integrity, guessing that they asked him to be their spy. [...]
- Obi-Wan travels to Utapau to hunt for Grievous.
- Street fight: Clone troopers, Bo-Katan's commandos, and Saxon's warriors battle in the streets of Sundari, with the Republic's forces winning the day.
Star Wars: Timelines, pages 100-101, "Jedi on the Brink"; emphasis added
Putting these chains of events together, the briefing occurs before Obi-Wan leaves.