Oxygen Not Included

Yeah it's likely shove voles. You can relocate them into an obsidian box with a steel door if you don't want to kill them. They are a good source of meat if you ranch them.

Since you've ruled out meteors another source of entombing in space can be rocket heat exhaust cooking debris. For example a dupe carrying algae into the rocket, gets distracted by downtime, drops the algae somewhere near a rocket. When the rocket takes off the exhaust cooks the algae->dirt->sand which can turn into a tile and entomb things.

so. now you've played this, what are your thoughts on it, compared to Factorio?

I vastly prefer this, as well as, rimworld, etc. where I don't have direct control, and are instead giving orders to, and keeping the npcs alive. Feels like there is more purpose.
The secondary factor is the death spirals. germs causing sickness, sickness causing crops to rot on the vine, causing starvation, etc. things like that. when something goes wrong, it typically gets harder to fix, due to the problems it causes. dupes dying from your mistakes or poor planning.