Either way, when u use power trick no matter of your ev you'll get koed unless you use focus sash. Here's what happens
Shuckle used power trick
Pokemon x used any move that does damage
Shuckle fainted because of its loser defence after power trick.
OR
Shuckle used power trick
Pokemon x used a move
Shuckle held on with it's focus sash
Shuckle used rock slide
Pokemon x used a move
Shuckle fainted.
It's even worst if you go last.