The fireball, along with the hits the chain golems are starting to inflict, are finally taking their toll on Maiabel. It's a small miracle that she can even still stand at this point. Her will may be strong, but her body is beginning to fail her. And, while she'd normally pride herself on selflessly serving her master... a servant is no good dead. Not unless her death serves some purpose - and it would not, at this juncture.
Carefully, she backs away from the chain golem, just enough to get some breathing room, before sheathing her left shortsword so that she has a free hand to make the required gestures for the healing spell she uses on herself.
Spoiler: Actions
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Five-foot step south.
Move action - Sheathe my off-hand shortsword.
Standard action: Cast Cure Moderate Wounds on myself. (2d8+4)[19]