DL - good to hear the new job is coming along. That was a great thing to do, helping somebody out late at night, who
really needed the help !
I don't know the IN code, but just wanted to make a general comment on light colour (color down your way

).
Check what is acceptable
before you buy/use an add-on flashing light. Example, here - Green is volunteer fire, Blue is often used for snow removal equipment, Orange on farm or construction equipment. I picked up a Blue LED flasher mag-mount at my NH dealer a few years ago, that I use on my tractor at night. Still on original AA batteries.... might be a good option for your use, as you don't have to futz with using a cord on somebody else's vehicle (blown cig lighter fuse....) if that is where you need the flasher to be.
If you are on the side of the road helping someone, I'd
hope an understanding LEO would cut you some slack, if you happened to have the wrong colour flashing light in use for your area.
Moving along the road with the wrong colour of Non-OEM flashing light is usually a big No-No in most areas (Red being the obvious problem), but again, I don't pretend to know your specific state law.
Not nagging about lights, would just hate to see somebody with good intentions get a ticket (and/or lose license points) when trying to help somebody out...
Rgds, D.