Is that a crypt in the middle, and is it that of St. Vladimir?
No it is not. Look at the pictures on the following web sites for a better picture. What you are seeing is a metal fenced enclosure in front of the iconostasis. Because this is a cathedral church, during major feats days it is usually very crowded with many people pressing against eachother. As a result these enclosures were set up to prevent the press of the crowd from interferring with the liturgical celebrations. It allows the multitude of hierarchs, clergy and servers to move in procession etc during liturgical celebrations.
This cathedral was built for the celebration of the 900th anniversary celebrations of the baptism of Kyivan Rus in 1888.
Unfortunately, the iconography is by major "artists" of the period in the 19th "Imperial Court Style" of painting rather than traditional church iconography.
Consult the following web pages for better pictures:
http://ukraine-today.com/culture/religion/cathedral.htmhttp://www.ukraine-gateway.org.ua/GATEWAY/gateway.nsf/basicv/0103020603?OpenDocument&Click=http://www.patr-sobor.org.ua/index2.htmAslo on Vesnetsov paintings:
http://www.art.com/asp/display_arti...word=Victor+Vasnetsov&CTID=633344090