Disclaimer: I don't know what I'm talking about.
I would think if you told them you wanted the cash pay price, you should be able to get it done easily on your own dime. You have to pay it in full, upfront. That's what a friend does when he doesn't want to run stuff (like a colonoscopy) through his insurance ... because when he mentions insurance, the amount he ends up paying towards the deductible is much higher than the cash price without insurance. It might work for a second opinion.
Reread Disclaimer at the top
Jun-2016 CRC Surgery
Jul-2016 Stage 4, inoperable lung mets
Aug-2016-May-2018 Folfox, 5FU & Avastin, 5FU, Folfiri & Cyramza; beg in Oct-2017, receiving Vitamin C & Quercetin by IV every week
Jun-2018 Taking a chemo break; preparing for surgery
Oct-18 Recovering from YAG laser surgeries (Germany) on R and L lungs, 11 mets removed