One thing seems certain he knew who was in that car. Most police and rescue services will not announce names over a radio of victims. That likely rules out someone with a police scanner unless it was an analog cell phone call that was intercepted and the alleged Captain Clark was a mental case who just likes to respond to emergencies.
I just found this on a Google search for "bridge collapse Oklahoma":
USMA at West Point website has an article on the middle of the page: Graduate dies in Oklahoma bridge collapse: 31 MAY) Capt. Andrew Clements, 35, a 1991 graduate of the U.S. Military Academy, was among those killed Sunday in the I-40 bridge collapse in Webbers Falls, Okla.
But the link is broken! The other links on the page aren't broken!