Yeah xray machines usually do it by placing the control panel in a separate room (That you want anyway to reduce the amount of exposure the machine operator gets). The xray dose exposed is safe anyway, as long as it makes sure the machine doesn't continuously stay on. Tho the machines still likely have microswitches on access panels leading to the high voltage stuff, since those parts are actually more dangerous and can kill a person in an instant.
They don't have any interlocks. I have a large rotating anode veterinary machine and a smaller dental machine and I have worked on a handful of others of both types, I so far have never seen one with any sort of interlock on the access panels, you could unplug the HV cables from the transformer to the tube head and the machine would quite happily energize the transformer if you push the exposure switch. They rely on the fact that they are not sold to the general public and are typically only accessible to qualified individuals.
They DO have protection circuity that prevents over-exposure, typically one side of the transformer primary is switched by a SSR that controls the actual exposure and the other is switched by a mechanical relay. The relay closes, then the SSR fires the exposure then the relay opens. If it detects that there is a problem with either of these it will terminate the exposure.
Modern machines are all inverter based, I have not had to service one of those yet.