Will I die? Drag Radials in the Rain

Et street s/s are probably better than the 'R"s in the rain, but if you keep the speed down, use common sense going around corners, you should be okay. I don't think I would try it on et street radial pro's
Make sure your tires are hard enough for chassis dyno use. I think I would check the sidewall for max psi, and run that.
Normal street tires would be better for the trip..... and probably the dyno!

No wipers? I'd probably reschedule. No wet tires on the dyno that way.