You've done your best, so don't worry about what happens next. Nevertheless, lets see if we can hold on for the rest for just a little bit longer. With your metal coat, you should be able to withstand the slash. So Relax to gain back as much energy as possible. For your last action (Because you'll very likely get knocked out by the swift) use Toxic before he can use Swift - spit it out as fast as you can. With him so close after the Slash, you might not have to aim much. If somehow or other you're still conscious and have energy left, use Scratch .

Serafina (Meowth, Female): Relax ~ Toxic ~ Scratch