SHV and MHV interconnects are often abused in this manner. It's not strictly acceptable to exceed the working voltage rating, but there are precious few options for HV connectors and minimal hazard for low volume products intended to be operated by trained personnel.
If the connector is going to be subjected to 10kV continuously/long periods of time then I'd think twice about this, but if it is for intermittent use then I wouldn't sweat it.