There are 3 basement doors and the additional cost would be about €300 per door.
Even if money is no object, what’s the point of casting pearls before swine, or who down there does style inspections, or slips the favorite daughter business cards of divorce lawyers if you’re no longer proper door-wise?
My account says it could still make room for 3 x 300 euros in an emergency, if you absolutely don’t need them. One is happy to help.