Turtles All the Way Down

The work I'm currently querying has a bit of a long intro. I've gotten mixed feedback on it. Some people think the writing is strong, others think it's too slow. My crit group suggested cutting it back, at least. I've almost resigned myself to cutting it and yet I sit here, feeling more like I hold a knife than a pair of scissors, unable to start. Normally I have no problem with revising. When I see sentences and paragraphs that don't work I'm eager to re-write them until I feel they're perfect. (Strange how those sentences always seem to grow back -- like crabgrass.) But in this case I'm revising something I think is good. Cutting into it doesn't feel right. All I can think of is the "turtles all the way down" story."

Don't know the "turtles all the way down" story? Here is is:

Bertrand Russell (or some other agnostic scientist, in other versions of the story) is giving a lecture on the universe. Afterwards an old lady comes up to him and says:
"Very interesting lecture, young man, but you're completely wrong. The universe sits on the back of a giant turtle."
Russell says: "All right, but what does the giant turtle sit on?"
Lady: "Another turtle."
Russell: "And what does that turtle sit on?"
Lady: "Another turtle."
Russell: "And what does that turtle sit on?"
Lady: "You're not listening, young man. I'm telling you, it's turtles all the way down!"

Revising this is like pushing one of those turtles out of line. And it's a long, long fall to the bottom of the universe.

Yes, I know this is the "kill your darlings" rule. Any advice on "giving-your-darling-a-haircut-but-not-chopping-off-its-head?"