Another reason they're often together: Anakin's response to possibly dangerous situations (when they're not involving people he's personally invested in, anyway) can generally be summed up by YOLO. So it's just as well Obi-Wan was there to be the more sensible of the two.

"Here goes nothing," Anakin says once the containment field is on.

Maybe they hadn't found the way to open it with purely physical means but with the Force there's little that can remain hidden for long. "Should just take the right nudge..."