The three attacks mentioned just before the end of 7-8 am were a Baltimore mall, LA subway and Chicago Hotel. However when CTU briefs the president they talk about casualties in St. Louis rather than Chicago.
The crates of C4 in the storage unit would have contained an enormous quantity of explosives. While it is correct that gun fire would not set it off, the hand grenade would. The explosion would have been much larger and completely flattened the building and severely damaged those around it. There would have been no intact body or computer to examine.