Dog do you remember how Reid tried to initiate the explosive? I recall him trying to light something with a match or lighter.
If Reid was trying to burn the C4 that would not work. C4 will just burn and not detonate. However, if C4 is compressed while its burning, it may explode. Maybe he was going to stomp on the burning explosive in his shoe? That's not a very reliable way to initiate an explosive.
I wonder if he had a non-electric blasting cap with fuse wuth him too? I didn't hear much of the details...probably because the authorities didn't want to give out ideas to other would-be terrorists.