If the images are important, I wouldn't process the roll straight away.

I'd shoot 2 or 3 test rolls of nothing subjects, and processes sections these rolls in various combination of dilutions and times in your various developers to see what works best to save a gross over-exposure.

Once the correct combination is found for your working environment, then process the booboo roll.

I don't know Ilford 3200. I find Fuji Neopan 1600 isn't a 'true' 1600 for me. It's more of an 800 ISO film pushed to 1600. Perhaps Ilford works similarly, so a 100 ISO rating isn't necessarily 5-stops over-exposed.

Anyway, you'll have amazing shadow detail. (Grin)