Digging my way out

This is the northern end of the stone cellar at Gamone (the place where wine used to be produced):

Because of the massive tufa arch at the top, I imagined for a long time that this had been a northern doorway into the cellar (which had a similar alcove at the south, along with a big opening at the east into my house), and that it had been blocked up by earth in circumstances and at a time that remained unknown. I now know that this impression was false. The earth that obstructs this "doorway" has been there since the beginnings of time. Seen up close, it looks like this:

It's a dense structure of small stones and dry clay, with no signs of vegetation. Unlike the surface ground around my house, within this conglomerate, there can be no presence whatsoever of shards of roof tiles or fragments of tufa (otherwise my "theory" about this soil would be wrong). Indeed, it's quite moving (and tiring, too), at the level of the ground floor of my house, to be hacking into earth that has probably been there untouched since the end of the Miocene (5 million years ago), by which time the French Prealps had arisen, irregularly, and folded into the kind of wavy surface structures that we observe today. [If anybody wishes to challenge my geological explanations, I would be happy to hear their arguments.] That means that the stone walls of the cellar have in fact been built up against the original earth embankment, using it as a natural formwork.

The pick and shovel in the first photo indicate that I've recently started to dig my way up out of the cellar. In a nutshell, I wish to replace part of that archaic earth by a staircase, so that I can climb down into my house from the place where I park my car and store my firewood. I prefer to handle this task manually, at a snail's pace, rather than calling upon somebody with a mechanical shovel, because the ancient stone structures must not be harmed or weakened.

ADDENDUM: On rereading the above post, I realize that I've introduced a puzzle, and then failed to examine it. Why would the builders of this cellar have placed a "doorway" up against an embankment of solid earth? I see two possible answers.

(1) Maybe it was intended to be, not a doorway, but a simple alcove.

(2) Maybe it was indeed a future doorway, and the builders intended to do exactly what I'm starting to do today: remove the earth. But they simply never got around to finishing this task.

The first answer strikes me as strange, because I fail to see the possible purpose of such a massive alcove, backed up by bare earth (which extended further up beyond the level where we now see the daylight).

The second answer seems to be more plausible. But, in that case, why didn't they finish the job? Well, maybe they were prevented by harsh circumstances, of one kind or another, from finishing the doorway. In the history of the Choranche vineyards, there are two significant dates. 1593 marked the end of the Wars of Religion, during which Protestant invaders had totally destroyed the vineyards. 1789 was, of course, the date of the French Revolution, which put a permanent end to the time-honored role of the Church in the local wine industry. So, the wine cellar at Gamone was probably started at some time between these two dates. In the middle of this period, in 1709, the vineyards were destroyed by an exceptionally harsh winter. So, between the Protestant attacks, the harsh weather and the final death-blow of 1789, we can choose between calamitous events that could well have prevented the completion of the doorway. I would imagine, above all, that the winemakers became accustomed to a cellar with a single doorway (the one I use today), and the idea of completing the northern doorway, by removing all that earth, probably became less and less urgent.