  The proper motions of the three stars ejected from Orion's OMC1 cloud core
are combined with the requirement that their center of mass is gravitationally
bound to OMC1 to show that radio source I (Src I) is likely to have a mass
around 15 Solar masses consistent with recent measurements. Src I, the star
with the smallest proper motion, is suspected to be either an AU-scale binary
or a protostellar merger remnant produced by a dynamic interaction ~550 years
ago. Near-infrared 2.2 um images spanning ~21 years confirm the ~55 km/s motion
of `source x' (Src x) away from the site of stellar ejection and point of
origin of the explosive OMC1 protostellar outflow. The radial velocities and
masses of the Becklin-Neugebauer (BN) object and Src I constrain the radial
velocity of Src x to be V_{LSR} = -28 +/-10 km/s . Several high proper-motion
radio sources near BN, including Zapata 11 ([ZRK2004] 11) and a diffuse source
near IRc 23, may trace a slow bipolar outflow from BN. The massive disk around
Src I is likely the surviving portion of a disk that existed prior to the
stellar ejection. Though highly perturbed, shocked, and re-oriented by the
N-body interaction, enough time has elapsed to allow the disk to relax with its
spin axis roughly orthogonal to the proper motion.
