Well as far as I've observed and noticed, they will only use the opponent's power if the opponent's power is higher than theirs, otherwise they will just use their own.
The correct one is rogue.
Unless blocked, it copy the opponent card "base" power (either lower or higher than your own power).
Hello fraggle is this a bug anyway:
tanaereva with its bonus with 7 pillz fites with selsya with 8 pillz selsya wins i guess dat wat happened?
As you know, in all rooms (except the danger zone), round outcome are not totally predictible, attack represents "chances" of winnings.
Read the rules for more details.