Think about it, Cummings, the SOD, Spencer as a stooge, Audrie as a confident inside CTU, Someone inside let Palmer know about the gas or the gas was planted during Palmers administration with his knowledge or Sherry Palmers Knowledge. Remember this gas was burried in a bunker beneath the foundation of the building and it is of US origin If I recall.
I am really curious to find out how Palmer knew about the plot.