Due to the degeneracy of its n=2 states, the potential between a metastable 2S hydrogen atom and a conducting surface falls off as -1/r^3 asymptotically, in contrast to the usual retarded van der Waals potentials, which fall off as -1/r^4. This affects the quantum reflection amplitudes and causes the apparent space shifts, which express the time involved in the quantum reflection process, to diverge to large negative values at threshold.