My first thought was that perhaps some of these last minute explosions were like celebratory gunfire[0]. But no, it seems that people were still desperately trying to kill each other knowing full well they only had hours, minutes or even seconds left to do so: "the cease-fire would not come into effect for a further six hours - at 11am ... the final day of WWI would produce nearly 11,000 casualties, more than those killed, wounded or missing on D-Day ... Just minutes before 11am, to the north around Mons, the 25-year-old Canadian Private George Lawrence Price was on the trail of retreating German soldiers ... But Pte Price's death at 10.58 was not the last. Further south in the Argonne region of France, US soldier Henry Gunther was involved in a final charge against astonished German troops who knew the Armistice was about to occur. What could they do? He too was shot ... It was 10.59."[0] Madness.
[0] https://en.wikipedia.org/wiki/Celebratory_gunfire
[1] http://news.bbc.co.uk/1/hi/magazine/7696021.stm