Geez fruitbat, that's pretty damn scary. Make a believer outta a person.
Apparently the after shutdown warning could occur after a fairly long ground idle at high ambient temps and was caused by high oil temperatures.
The DC-4M was a pressurized version of the DC-4 re-engined with RR Merlins. The early models had no shortage of teething problems, not the least of which was false fire warnings. I had a friend who flew them as F/O, and one day between Toronto and Winnipeg all four went off at once. Walt said he nearly soiled his skivvies, but the Captain just said a few choice words, cancelled the bells and whistles and kept on going.
Moose, which 748 was that, the one on Anticosti Island or the one in Churchill?