Are you X? Because Y is a common pickup line, compliment, joke, etc construction. Y has a double meaning that relates to X and achieves some kind of punchline.
take by surprise
to startle someone; to surprise someone with something unexpected. Oh! You took me by surprise because I didn't hear you come in. Bill caught his mother by surprise by coming to the door and pretending to be selling something.
As you might imagine, death can happen suddenly and take someone by surprise (unexpectedly).
He was so young. His death took us by surprise.
Take me can also mean have sex with me (Urban Dictionary: take me). So I reason that in this context, take me by surprise more or less means have sex with me and make it a surprise, or surprise me with sex.
If you change it to 'cause I want you to take me, it doesn't sound quite right. Perhaps it is because the second option sounds more like a request to die.