The title comes from A New Hope, where Darth Vader says to Leia, "You weren't on any mercy mission this time" [7:47].
6:50 - Sinker: "Comin' here was a bad idea."
Boost: "I'm beginnin' to agree with ya."
In The Empire Strikes Back, Luke has the same response to R2's beeps: "If you're sayin' comin' here was a bad idea, I'm beginnin' to agree with ya" [43:55].
8:38 - C-3PO: "Impossible clones!" He similarly describes Han Solo in The Empire Strikes Back: "Impossible man" [7:40].
10:00 - C-3PO: "I have a bad feeling about this."
10:21 - C-3PO - "I suppose that could have been worse" and after rubble traps him and R2, "Now it is." In A New Hope, there's a similar exchange in the trash compactor. Leia says to Han, "It could be worse," and after an unsettling noise, he replies, "It's worse" [1:19:41].
12:04 - C-3PO (to R2 as bugs fly around him): "Did you see that?" Perhaps coincidentally, he asks a similar question (also to R2) at the beginning of A New Hope: "Did you hear that?" [2:47].
12:39 - C-3PO (in response to a tree saying he does not belong): "I heartily agree; being here is a terrible mistake." He uses the same expression in A New Hope after Luke suggests he wait outside by the speeder and says they want to avoid trouble in the cantina: "I heartily agree with you, sir" [45:45].
17:01 - C-3PO: "R2, we're doomed." He also says "We're doomed" twice (both times to R2) in A New Hope [3:04, 16:02], once (to Han, Leia, and Chewbacca) in The Empire Strikes Back [1:00:38], and once (to R2) in Return of the Jedi [10:03].
17:47 - C-3PO: "Riddles are my specialty." He pronounces "specialty" with five syllables, just like Obi-Wan does in Revenge of the Sith when he tells Palpatine, "Sith Lords are our specialty" [12:14].