This came up in my last game and I was unsure of the answer so I made a quick ruling based on what made sense at the moment, and today after going through the rules I'm still unsure what would be the official answer.
Are the movements in the following scenarios possible without the need to Tumble Through? My common sense says no, but I couldn't find anything in the rules to confirm this, and I'm starting to think the RAW answer may be yes.
The first conflictive scenario is this:
And the second is this:
Players are blue, enemies red, walls black.