I actually managed to find a spot between two of the non-destructible big rocks where I couldn't back off again, but I was asking for it, attempting to squeeze through an opening I was pretty sure wasn't intendet to be passed...
Near that area with the shielded "button" to open a force field to another area I encounteded a triangle of missing material...
I really loved the physical interactions you get with the rocks and the mineral bits. Not being able to get some sort of healing (despite the point when I recognized there were upgrades ready to be used ;) ) wasn't actually so bad when I encountered that I respawned at some point nearby when I died once...