In Star Wars: The Clone Wars Season 5 Episode 8 Bound for Rescue, Grievous defeated Kenobi & gained control over his Republic starship. Moments before he was going to collect data from data banks of ship, a holographic message of Kenobi appeared saying that the ship was about to self-destruct.
What was the point of alerting Grievous when he could be killed silently?
When it comes to diverting him from data stealing, I think killing Grievous was more important than saving some tactical data. It could change the wind of The Clone Wars.
Plus, the message wasn't that effective to save data if data security was poor enough to be broken within seconds. B1 Battle Droids already had orders after all.
Why didn't Kenobi try killing Grievous silently?