It is based on the higher performance of "Starlink Business" [0] that has more performant hardware, increased throughput, priority, and support and which, in the U.K., is billed at "... £400/mo for service and £2,410 for hardware." It presumably also has to be a hybrid with the roaming services such as RV and Marine which may imply having to dynamically adjust satellite and ground-link paths. With the number of terminals in operation inside UA it is also possible there is a dedicated ground station in, or close to, Ukraine which would also assure very low latencies.
As others have said, the demands of military use probably require 24/7 dedicated support and monitoring with real-time threat detection and evasion from skilled engineers at SpaceX/Starlink and actively monitoring the satellites passing over Ukraine, Russia, and Belarus.