Is there a way to rescue Sev at the end of Star Wars Republic Commando

Yes, it is very complicated and only the most skilled players can accomplish the task.
First you may unlock all weapons and go into your inventory and carry you lightup sword to the opening at Ninus Tomb. From there you befriend an African whale whom will teach you the meaning of life. That's when you realize that you should stop playing star wars video game and get a life. So noyou can't really save Sev. Hope this helped!