  We analyse numerically the transitions in an Unruh-DeWitt detector, coupled
linearly to a massless scalar field, in radial infall in (3+1)-dimensional
Schwarzschild spacetime. In the Hartle-Hawking and Unruh states, the transition
probability attains a small local extremum near the horizon-crossing and is
then moderately enhanced on approaching the singularity. In the Boulware state,
the transition probability drops on approaching the horizon. The unexpected
near-horizon extremum arises numerically from angular momentum superpositions,
with a deeper physical explanation to be found.
