Abby had to, briefly, surface because she did forget to keep her breath watching someone Team Rocket themselves into the ocean. Glad she didn't go first, laws of physics just do not give a fuck about their plans. This was a lot more 'scalpel' than 'woodchipper' work. So while she waited for Dean to get back she created a small air current from her knife and used it to try and push slime together into controllable sizes.

Glad you're not dead. That'd be awkward to explain.

Can you try doing that and not being Wile E. Coyote?

She used her knife, and the air currents she was making, to start gathering a ball of sludge, then touched it with the tip of her knife to freeze it. It expanded, more physics shit, ice ball to the surface.