Rich Uncle is getting on in years and no longer can safely navigate the stairs in his beautiful three-story (plus basement) mansion. So, following his doctors advice, he pays $250,000 to have a four-story elevator installed.

Immediately prior to installation of the elevator the mansions FMV was $7.5M. With the new elevator the mansions FMV is $7.75M. Ignoring the %-of-AGI floor, what is the amount of Rich Uncles medical expense deduction, if any, on account of the installation? Why is that the correct amount?