Accidentally EVA'd mid transfer. Sending a rescue mission shortly. Replay 4786821845186980442 (WARNING: big planet) This was only a visual bug I think - commander re-appeared inside the Astreus on arrival, though didn't want to fire any of his weapons.
An eva in inter-planetary space wouldn't have the ship fly away from your body at huge speeds. When you eva, you are still going approximately the same speed as your craft, so this kind of shenanigans would never happen unless you just eva'd then left your computer for and hour. ☐ Not REKT ☑ REKT
Same with me. The Astraeus would continue to its destination, but its cargo would mysteriously EVA and float somewhere in space. It reappears upon arrival. An image of this bug can be found here.