If you watch the full testimony from Natalia Usmanova - not the clipped up version that cut out these parts shown in western media - she states just that:
She went to the plant on her own accord. According to her the military members wouldn’t let her leave for her own safety. She is now alive and well and out of Mauripol. She wasn’t used as a “meat shield” she wasn’t tied up and bound as a prisoner or hostage. At that point the soldiers had to worry about the majority and not about one or two civilians thinking they know better than the soldiers on how to get out alive. And out of thousands of civilians in the plant, you can only find one that says she couldn’t leave the plant whenever dude wanted? SMH.
oh and BTW she never claims she was held hostage.