ESD flooring in electrical room
The question is not only one of limiting the current in this environment but also having a current limiting resistor with an appropriate voltage rating. The common voltage rating on ESD current limiting resistors is around 250 volts. Any mats that would be put in place would need to be certified for use in higher voltage environments.

You would also have to give thought to the test equipment that is used to ensure that the mats are still meeting specification. In this higher voltage environment, I would like to see something that is the equivalent of a HiPot test.

Here is one reference from an ESD mat manufacturer that specifically recommends against mats in environments where the voltage is > 250 volts. They also list several other references that may prove helpful in your investigation.