As Glamador said - LOL:
for (i=0; i<=2 or 3; i++)
{
- shoot the boss all the way <;
- wait for him to fire a zombie, move >;
- let zombie enter the gas pit, bind-song him and drag him <;
- release him somewhere in the middle of the map, shoot boss <;
- bind zombie again and fast-release him near the boss (before he starts his whirlpool);
- hook onto a wall so you don't get sucked;
- you'll see he eats the zombie and implode

;
}