A method for advancing a rigidizable medical device may include rigidizing a portion of an outer element of the device, and while the portion of the outer element is rigidized, advancing an inner element of the device relative to the outer element of the device by a first preestablished length of advancement. The method may also include, after advancing the inner element, relaxing the portion of the outer element of the device. The method may further include, after relaxing the portion of the outer element, advancing the outer element of the device relative to the inner element of the device by a second preestablished length of advancement.