If they don't have enough phones that get priority on the packet routing to distribute to key staff, then they need to bring the satellite phone link with them.
Guess they don't want to pay for Starlink since X Man Bad, like Orange Man Bad.
Starlink would not be phones it would be a portable Mini dish set up linked to a Wi-Fi router. But with tens of thousands of phones all with Wi-Fi on and searching for signal it would easily have overloaded the Wi-Fi CDMA spectrum. The more phones the higher the noise floor until saturation even if the phones are not connected just searching for signals. You need dedicated spectrum. Which AT&T has so does Iridium and the UHF band of Milcomms all are dedicated to LEO, or warfighter. SS is certainly authorised to use national technical means if they ask for it. At the very least that should’ve brought in a UHF repeater on dedicated LEO freqs with a dozen encrypted dedicated radios then handed them out like Oprah any you get a radio and you get a radio...to every agency there. You know maybe at the group meeting beforehand to coordinate security...