col·lat·er·al·da·mage
Wesley is stronger than most people give him credit for; certainly more than his father does, and at least a bit more than Faith. She wants to hear him scream; she will not. She cannot break him. There is only one who holds that power.
He is, however, grateful that Faith only manages to make it through blunt and sharp before Angel arrives, but it is small, as victories go. There is an unspoken understanding, a communication of sorts between he and Angel, despite the fact that he is near delirious from the pain and loss of blood; at the same time he throws himself back from the blade Faith presses to his throat, Angel leaps forward, distracting Faith and engaging her in battle, and Wesley is safe, for now. He is helpless, still bound to the chair, and frighteningly secure in the knowledge that this woman, so far gone that there's no way she can be saved, will kill Angel. His Angel. He works frantically to free himself, knowing that he must come to Angel's rescue the same way Angel has come to his.
When Wesley reaches the alley, a kitchen knife clutched in his battered hand, to see Angel embracing her, soothing her, it is then that he breaks. The knife clatters to the ground, and Wesley's blood and tears mingle with the rain as his heart is shattered.
~*~
She could've taken Cordy; Angel knows this. There is an element of personal gratification here - Faith blames Wesley for her own failings, hates herself and so, hates him - but it is mostly because she can sense it. When she sees them together, the three of them, she can sense the dynamics in the group. Wesley is rapidly becoming Angel's right hand, and without him, he is crippled. There is more to it than that, but she knows only what she has seen, and she has not been watching them long.
It is worse than he thought; Faith has made a makeshift blowtorch from a can of aerosol and a lighter, and she is threatening Wesley with it. Wes, for his part, looks disturbingly calm. So calm, in fact, that Angel fears he's too late, until he's absolutely sure he's not imagining Wesley's erratic heartbeat. Their eyes meet, and a connection is made. Both men take action at the same time, as though it were an oft-discussed plan. Angel does what he can, what he must, to get Faith far away from Wesley.
Standing in an alleyway in the middle of the pouring rain, Angel finds himself holding the small woman - murderess, slayer, torturer - as she sobs out her sins. On the edge of his perception, there is a metallic sound as a blade hits pavement and the watered-down scent of betrayal and blood.
The collateral damage is immeasurable; in saving Faith's soul, Angel has lost everything.