Seems like emerge stops after tests failed... tinderbox _really_ needs that feature to be around :|
Sorry about that. It's fixed in git now: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=3d2c78303bb3bfb5a9174686e4069770602eeda2
This is fixed in 2.2_rc69.