Maybe, maybe not. As long as he has 9 of us who've proven ourselves, he doesn't need the rest. And if his threats were real, seeing five people disappear because of his power could also have the possible side effect of cowing people into bending to his will.

[He lowers the crossbow, reaching for another bolt at well. He really didn't like the recoil on these, but other than that they were more convenient than something that would require him to get up close and personal.]

Honestly, I don't know. It was a terrible thing, but who knows what the Teishu would have done to Mako otherwise? Mako said 'Do it'... Maybe he wanted it that way.