Why does the player begin on a life raft?
The player survives the failed opening encounter and is rescued by the carrier Endurance after the original Wings of Theve pilot is killed.
Confirmed explanation
That defeat creates the circumstances for the protagonist to inherit the Rex callsign and join the remnants of the FCU force. It also establishes the campaign’s losing-war tone.
What is not confirmed yet
The complete opening mission and exact sequence of the rescue remain subject to the retail story.