just to be clear, you can enter the room, grab the rod and leave without fighting the T'rang at all...

[spoiler] you start a fight in the hall way out side against bugs (thats normal bugs, not T'rang) and the two guards will fight them or more offen just run off... then you unlock the door , press combat | run and open the door, you have time to run in grab it and run out... the room will show agro but the combat ends when you leave and they go back to their jobs.[/spoiler]