Plot hole: When the team manage to create the cavern with the buried stargate they send Teal'c through to drill his way out, but wouldn't it be safer (and significantly faster) to fire a missile or two through and blast their way out? They have no idea how deep the stargate is buried, or under what type of rock, so sending Teal'c with only four hours of air seems suicidal. (00:35:00)
Suggested correction: Except that sending a missile through would only cause the rocks to cave in onto the Stargate again and could possibly make it impossible to reopen the Stargate. If they could reopen it, they would just end up creating the same cavern. Not to mention the fact the danger to life on the planet if a missile did make it through and ends up exploding on the surface.
Except that if the gate is active, anything falling down on it would be destroyed, so if anything you would still end up with a cavern if material soil bound together as it was falling towards the gate, OR you would end up with a crater which would be Teal'c's objective.
It's not about the rocks being destroyed. It's about if the Stargate ends up shutting down and the rocks creating an iris, making it impossible to establish a wormhole.
Other mistake: When the Asgard arrive to save the day they start by beaming out the Goa'ould but Teal'c gets left behind. He should have been beamed out with the rest of them.
Suggested correction: The Asgard know about Teal'c from the season 2 episode "Thor's Chariot". In that episode they upload his DNA profile into the Asgard computers so that he is not beamed away with the other Jaffa in that episode. His profile would have been kept so that he would known in any future contact situations with the Asgard.
This correction seems to have been made without watching the episode (or remembering the episode). The Asgard spoken of are from an alternate reality when they never met Teal'c (and don't have his DNA). One could suggest that alternate reality Carter told them about Teal'c, but there were two of them, and she wouldn't have known alternate reality Teal'c was later killed.