  The lifetime of the recently discovered $2p$ emitter $^{67}$Kr was recently
found considerably below the lower limit predicted theoretically. This
communication addresses this issue.Different separation energy systematics are
analyzed and different mechanisms for $2p$ emission are evaluated. It is found
that the most plausible reason for this disagreement is a decay mechanism of
$^{67}$Kr, which is not "true $2p$" emission, but "transition dynamics" on the
borderline between true $2p$ and sequential $2p$ decay mechanisms. If this is
true, this imposes stringent limits $E_r=1.35-1.42$ MeV on the ground state
energy of $^{66}$Br relative to the $^{65}$Se-$p$ threshold.
