Character mistake: At the end, Vala and Mitchell establish a wormhole and let Teal'c and Jackson know. Almost a minute passes before Teal'c and Jackson get back to the gate and Jackson yells "run" because they need to get through the gate right away. Obviously they're detained, but after being let go, Mitchell says they're sending the iris code now. This is something that should have been done sooner, especially after hearing gunfire, so they could be ready to go through when Teal'c and Jackson arrived.
Suggested correction: OR... after hearing the gunfire maybe it was smarter to wait until they verified that it was Teal'c and Jackson who prevailed. Otherwise, they risked leaving the gate open to a hostile force.
Perhaps they waited, but they still would have sent it when they saw them, which the didn't. And they've never waited like that before.
Plot hole: And the end, when Vala and Mitchell activate the Stargate home, SG-1 is delayed in being able to step through because they are detained. However, the whole time they're detained by the gate, there's no radio transmission from SGC. Later we find out they're coming home early, so on SGC's side, they just had an unscheduled off world activation and would know it's from the planet SG-1 is on, and they would radio for an update. None of that was done so the conversation could happen.