Bruce's phantom, being comprised of material that had originally been Bruce's own skin, reacted the same as though Zelriane had made contact with his body. 

Moving based on gut feeling and tactile sensation rather than sight, he reacted a little faster than he otherwise could have. The blade in his right hand dissipated and the blade in his left hand lengthened. With an upward flick of his wrist, the blade came in an arc toward Zelriane's outstretched hand, intent on cleaving through palm, fingers and forearm as much as possible. 

A moment after that, the two clones nearest either flank stepped forward, slashing crosswise to send slicing waves of Ki at the encroaching threat.