The measured temps might not reflect this. In 1, the heat quickly floods the room while in 2, the heat takes a while to filter out. A thermometer in the center of the room may hit a higher, faster spike in 1, a lower, longer lasting rise in 2.
“Heating up” is kind of vague.
Some engineered plastics are very conductive and receive microwaves very well. (Don’t ask me how I know :eek: At least it was a $5 part, not a $500 one.)
Others are pretty much transparent to microwaves.
It’s certainly plausible that a Glock receiver is made of such a conductive resin composite material.
One of the more spectacular suicides detailed in David Foster Wallace’s novel Infinite Jest was the self-demapping of James O. Incandenza, who reportedly cut a hole in the microwave oven door, stuck his head inside, and ran the oven long enough to kill him. Even though he plugged the gap between the hole and his neck, he should still have had enough wiggle room to free his head once the heat got unbearable. Maybe Wallace wanted us to infer that Incandenza had monk-like mastery over the instinctive response to pain.