He blinks, a little surprised, but takes the knife like somebody who at least won't stab themselves by accident. That's all the capability he knows how to display, really. "Wait, you're swimming out after it?" He opens and shuts his mouth, slightly at a loss, then gives a resigned nod. There's no disrobing of any kind, but he starts after the nearest tentacle without any further hesitation, intending to stab and slice as well as he can. Maybe he can at least distract the thing long enough for Dean and Jo to actually save somebody.