Followup: Yeah, the heating idea is stupid. I admit it, and I didn't do that.
I'm in the process of setting up a second residence and I have a few extra bikes so I shipped them out for me and my wife. I shipped a couple of the redundant general tools I have but I didn't ship my decent Wiha wrenches that probably wouldn't have had a problem with this. I like the idea about using a torx driver but I didn't have one of those with me either.

I took the suggestion to buy a screw extractor bit for $2.89 and I did have a small adjustable wrench to grab it and turn it -- and that worked great. I heard the loctite make that satisfying snap sound and the screw just backed out.

Unfortunately I don't yet have a way to get that screw extractor to release from the screw ....... so I took another trip to the hardware and bought an M5 set screw and the job is done.