Though L can't see the grin, he can feel the tension in the air, the heavy pause before a potentially devastating blow to more than a sinner's skull. Though he's seen, firsthand, the grisly destruction that Tony's capable of, he vaults over the counter when his words seem to fall on deaf ears, clutching his ice staff and covering the distance between them in several long, urgent strides.

If Tony was of two minds, and at war with himself, L would eliminate the problem by eliminating an option. Heedless of the potential danger, he's reaching over Tony's shoulder, fingers latching the gun's safety before he's got a firm hold on the young man around his thin shoulders, pulling him away from the maimed and helpless attacker.

"Tony, it's over. I won't lose you over something so senseless."

Losing Anthony was already too much.