(It may have gone unnoticed by some at first, but it’s definitely in there. It’s apparently morse code of . . . - - - . . . that translates to an SOS signal. This is the isolated audio of it, but the placement and style of each signal in the tracks themselves are quite telling of the characters.)
Vah Ruta: SOS comes in immediately and is quite loud. Mipha is the most pacifistic of the Champions and would have been the first one to call for help. She’s also more a healer than a fighter and probably stood the least chance of defeating her Blight. She was likely the most terrified in their situation.
Vah Rudania: SOS also comes in immediately but is fainter than in Vah Ruta. Alongside being the least technology-inclined champion, Daruk has a strong sense of family and protection. He likely projected his fainter than the rest as he didn’t want to worry the others.
Vah Naboris: The theme starts out with a jolt of piano keys, followed by the faintest SOS of the four. Urbosa is very proud and, like most Gerudo, was very battle-inclined. Combining that with her Fury means she likely would have lasted longer in her fight and not sent out the SOS immediately. My idea is that Thunderblight was too fast for her and overwhelmed her. She would have been strong enough to defeat it otherwise, and the faint SOS was her attempt to send it as she bled out.
Vah Medoh: Although coming later into the theme than the others, this SOS is most prominent and the fastest. Revali likely lasted the longest in his fight and his prideful nature meant he thought calling for help was underneath him. But he even he was overwhelmed and eventually swallowed his pride to send the message. A comment I read explained it the best. “Revali’s call was rushed. It was frantic and panicked. It was a call only someone who knew they were going to die would make”
(Video Source)
