  We analyse a system in which, due to entanglement between the spin and
spatial degrees of freedom, the reduced transmitted state has the shape of the
freely propagating pulse translated in the complex co-ordinate plane. In the
case an apparently "superluminal" advancement of the pulse the delay amplitude
distribution is found to be a peculiar approximation to the Dirac
delta-function, and the transmission coefficient exhibits a well-defined
super-oscillatory window. Analogies with potential tunnelling and the Wheeler's
delayed choice experiment are highlighted.
