In the first X-Men movie (2000), at the final showdown, Magneto forces his powers upon Rogue so she can be the catalyst in his machine.
But if Rogue has Magneto's power, rendering him temporarily powerless, why didn't she use his powers to escape?
This is covered by the film's (surprisingly faithful) official novelisation. In short, she makes an attempt to use his powers but it turns out that Magneto isn't a complete.barking.moron and has factored this into his evil plans.
With his bare hands, he touched her face.
Suddenly she felt the incredible energy flowing into her.
She could see everything that he had seen.
She knew what he knew.
She saw all the death, all the horror.
Abruptly, he let go and staggered backward, his face white with shock. The machine around her came to life, shifting, yanking her hands down onto the handles. The rings began to spin, slowly at first, then faster.
She fought hard to let go, trying to use his power, his energy, to her advantage. And she failed.
Though she possessed his power, the machine was in control. She knew, from the images that had coursed through his mind, that he had thought of everything. He had planned it all—down to the last detail.
And she knew she was going to die.
She also knew that, from this point forward, the process could not be stopped. She knew that if Magneto had been standing here, in her place, he wouldn’t have been able to stop it, either.
A moment later, something shifted. The energy he had given her began to flow away, draining into the machine. Along with it went her own life force.
Presumably if she'd had more time, she might have been able to find a loophole but with the machine draining both her power and her life-force, she wasn't in any condition to help herself.