When a particle is moving with a constant speed in a corkscrew tunnel, it is traveling in a circular path as it moves forward. The path followed by the particle is a combination of two motions: linear motion (forward) and circular motion (around the circle).
When the particle exits the tunnel, it will continue to follow the combined path it was on before, which is the path of a helix. The helix is a three-dimensional curve that is the result of combining circular and linear motions, that is, the particle will move forward in a straight line, but also continue to move in a circular path around that line. The shape of the helix is similar to a spiral staircase, as the particle moves forward, it also spirals around the center axis of the tunnel.
In summary, when the particle exits the corkscrew tunnel, it will continue to follow the path of a helix, which is the combination of linear and circular motion.