Well that's a plasmid Sinclair's never seen before.

He watches the Sister fight him for a couple moments more before she relaxes and quiets.

When Jack sets her down again, her eyes are clear and there's color in her cheeks.

She's healed. Sinclair's not sure what he expected when Jack said he was going to start helping Doctor Tenenbaum rescue Little Sisters, but it sure wasn't a plasmid that does all the work for him. That woman doesn't get half the credit she deserves, if she's the one who invented this.