Creative Speculation

If you watch the close-up high res video of Tower 1 burning, at the moment Tower 2 is hit, the fire in tower 1 'pulses'. Why? Because the air handling systems of the two towers had interconnections in the basement. Pressure will escape wherever it can find release from the air ducts in the central support columns. If it finds a weak point at ground level, bam, that's where it blows out.

I would question the individual's perception of timing under those stresses/conditions. Human memory doesn't record like a video tape. It's constructive. And as such, it is incredibly fallable.

There are other forces to consider. The shockwave, like the P-waves of an earthquake spreading from the impact. The flex of the building, under 7.7 million foot-tons of torque. The resonance of the buildings, absorbing that momentum. If the flex of the building on impact knocks loose a 500lb slab of decorative marble sheet at ground level, and it falls 2 stories in the lobby and shatters, might that sound like a bomb exploding? I'm thinking: yeah, it does.