When pressure cooker is finished, carefully turn steam-release handle to venting position, and let steam escape; float valve will drop. (This will take 3 to 4 minutes.) Remove lid from cooker. Select Saute setting. Select high temperature setting, and bring to a boil. Add noodles, bok choy, and carrots, making sure noodles are submerged; cook, covered with lid resting on top, undisturbed, until noodles are tender, 3 to 4 minutes.