Flavel WFA6100W washing machine – large hole in tub

Went out to this machine last week. Problem was the door seal had popped off from the tub. Thought that was weird to start with, but assumed the spring perhaps had not been fitted correctly at the factory. I refitted, which involved removing the front counterweight. Function test all fine.

4 days later, customer reports machine has flooded the kitchen.

Reattended today and found a large hole in the tub just behind the front counterweight.

1) Did I overtighten the screws when refitting the counterweight? For future reference, what is the torque setting?
2) I found some dubious looking brown bits where the machine stands. Plastic broken off from tub largely unaccounted for, only a few bits found. Could it have been rodents?
3) Did violent shaking of appliance whilst spinning due to load or other causes weakened the tub and caused the door seal to pop off?

Lucie