Mortinomicon gone, locked out of Sanctum

I got the Mortinomicon, travelled to the Fellshrine Ruins and got the freebie 2x1 relic. "Put it in the altar!" she says.

However it wouldn't let me put it in the altar as there was only a 1x1 space there. I noticed the "CONFIRM" button was active so I pressed it. This expanded the altar and started a run with no relic (relic was still in inventory).

So I pressed the "reset run" button to try again, since I didn't want to do a run with no relic.

But now I'm screwed. The Mortinomicon is gone from my inventory, the altar has reset to 1x1 so it will only take the Mortinomicon, and I still can't put my relic in it. The Mortinomicon doesn't drop again when I go back to the Ossuary. I seem to be locked out of the whole mechanic.

That book is your one free shot. You need a Forbidden Tome to open the sanctum again, which is a random drop from enemies.

So a quest item is a consumable item? Wow, that's terribly explained then. It should at least come up with a warning message like "Warning: Resetting the altar will consume the tome, are you sure Y/N".

In fact I never even put the Mortinomicon in the altar - the game just auto-consumed it from my inventory when I pressed the Confirm button, without telling me.

It also leaves Divinia with a perpetual exclamation mark over her head...