Correct.

"I'm gone, but then, I'm not gone. So if I do leave, you can't be sure that I am gone, can you?"

sword in the stone?

Yep!

"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."

Jurassic Park

correct

"It's like it's a marriage of convenience and all it produces are dead offspring."

The Constant Gardener?

Yep...great line. Loved how it had 2 meanings.