There is a moment of resistance, and then his hand passes right through, though the contact will leave behind an ache like he's just brushed a live wire.

The phantom Yelena's knive drives deep into the other woman's abdomen, and she staggers. Something bursts between them, red and glittering like the residue on the walls, both here and above, and a small glass-and-metal tube falls from the woman's hands. If he's watching carefully, he might catch the moment where Yelena's eyes burn red; she rubs at them, as though brushing away grit, and her expression turns to horror as she looks down at the woman who's now slumped to the ground, breathing labored.

The vision fades. The static pulses in his ear again, urging him onward.