Heinrich - it refers to the size of your sphincter changing during a high- situation (half-crown is bigger than threepeny bit and dustbin lid speaks for itself) ie normal, pucker, full dilation!
As for the incident, the way the fuselage rotates is exactly what you would expect from a sling load still attached when you thought it was released and started to move away.
The cloud of dust is certainly the floats being fired and you can see the starboard skids ones inflated - the bright orange.
Lucky guys.