Berserker solves the problem like she solves all problems: By constructing a castle.

Hers befits a feline imperator. A three-layer kitty tower, with numerous nooks, ledges, sight lines, pillows and squeaky toy. It is abundant with places to lurk, places to preen, things to do and comforts to rest under. She has even painted a scintillating pattern of paw prints and smiling kitty faces along the side. 

She presents it to the cat with a craftswoman's satsifaction.

The cat takes one look at it and instead hops down a stormwater drain instead

Berserker picks up the kitty tower to use as a club to smash open the stormwater drain, the stormwater system, the earth itself and perhaps more besides.