The door slid inch by inch, then suddenly got much easier to push. Either someone had done something to the door mechanism, maybe carved a path in the floor, or...

...or maybe the Jaffa pulling the door open could have had something to do with it. From the way the two in the back were twisted to look back, the group had been about to move on and continue searching other rooms when they heard the door start to move.

Vala and the Doctor found themselves with three staff weapons lowered to aim at their faces. The heads split and sparked.