It’s even possible that the white truck was going to pull over to the side of the road like the red truck and that at that point the red truck was trying to merge back into the traffic lane. The white truck seeing the red truck trying to merge back over may have oversteered into the far left lane.
If, as Red said, “unfolded as the other two vehicles passed him” implies White lane shifted when passing Red. Could be Corzine’s speeding SUV got into White blind spot, and White thought it was clear to lane shift.
When an “emergency vehicle” is in a fast lane, barreling down a highway in traffic, anything can happen because people have to make quick decisions moving at high rates of speed. Some may panic.
That said, we now have to know why his emergency lights were flashing. Was there a true emergency, or was King Corzine just moving the peons out of his way?