Looking at the photo in #7, the tug cab has been lifted up and pushed sideways, its front left tyre has been deflated, and the tow bar is still connected at both ends and is bent. The tugs wheels are not turned, but are pointing more or less straight ahead.
The tug could not have caused this by driving into the nose gear because if it had, it would not end up 90 degrees to the aircraft, it would be more head-on. You can't drive into something sideways !
So the aircraft must have moved forwards - due to excessive engine thrust or ramp slope - which pushed against the tug and eventually bent the towbar. Then the aircraft hit the tug, turning it and and pushing it sideways, which deflated the front tyre probably by pushing it away from the rim, releasing the air. The tow bar shear pins probably did not let go because the force was mostly along the towbar, not twisting it sideways.