The line "come with me if you want to live" is actually kind of important. Its the first thing Reese says to Sarah Connor in the first movie. It's also the first thing Arnold says to her in the second. The fact that Arnold said it in the second one was to signify that, just like Reese, he was there to protect her (you're supposed to imagine she remembers that that was what Reese had said to her)
The "I'll be back" line is for pure comedic value though
