Irene's Arm on Clare did twitch at roughly the same time that Rafaela would be killing Irene, so it's more likely that indeed Irene is dead, killed by Rafaela.
Also, Rafaela has no qualms about killing her fellow Claymores, as the only one she cares about is her beloved older sister Luciela, and Rubel is using his information ABOUT Luciela to "own" Rafaela as his "pawn". And so, Rafaela will do whatever Rubel wants of her, and/or whatever she needs to do, for her beloved older sister Luciela, and Rafaela's mission to save-protect Luciela by returning her to being a Claymore or a Human possibly from being an Awakened, an AO. Rafaela would gladly kill all of her fellow Claymores, if it meant she could get her beloved older sister Luciela back. And indeed she did kill some or maybe many Claymores as the Org's... well Rubel's... "Assassin of the Org". Also, she thought that she what she was doing, was going to sacrifice her own life force, to give to her just killed Luciela by her own hands, and so to revive Luciela from the dead as a Claymore or possibly a Human. At least that's what Rubel told her would happen though he likely was actually telling her how to creater an Uber Awakened... my theory anyways in conjunction with Rubel's mysterious information ABOUT Luciela, hehe.