He has just started to grin when he turns, and his expression slides into total shock. He runs to her, crouching by her side, feeling sick. "Penny?" He swallows. "Penny!" His gaze darts around the room, returning to the shrapnel embedded in her stomach; should he try to remove it? Would that make it worse?
"...Billy? That you?" and the bottom drops out of his stomach, because she's recognized him, and she'll hate the Doctor like everyone else, but she's dying and-
"Penny-hold on-oh no, no no no no no-"
"Billy? Are you all right?"
He chokes, because of course, of course, she only ever cared about the people around her. "Penny-hold on-"
"It's okay," Penny says weakly, smiling; he stares at her, completely bewildered-how can it be okay? She's dying, and it's his fault-"Captain Hammer will save us."
For a moment he thinks he's dead; some piece of shrapnel from the roof has fallen and skewered his chest, but no, it's only the feeling of his heart breaking. Then he grits his teeth and stands.
"Captain Hammer won't save you, Penny," he tells her. "I will." He has no idea how, but he'll work that out as he goes along, and he finds himself humming a tune that quickly develops words.
"This appeared as a moral dilemma
'Cause at first it was weird, though I swore to protect you
I did not want to kill, but it seemed that I had to
Didn't hear what you said, but I think now I understand
And you have shown me the light...
It's a brand new day, and the sun is high
All the birds are singing, you're not gonna die
I won't hesitate, so don't you say goodbye
It's a brand new day-"
He needs the Freeze Ray, first; if only it hadn't burned out-but when he sprints to the tripod, he finds that it's almost completely undamaged. Only a few wires are out of place, and he can see it now, the circuitry is set so that after a few minutes the gun will overload itself and fail. It takes him about five seconds to twist the wiring back together, aim, and fire; a blue glow surrounds Penny, and she halts, like someone pressed the "pause" button on a remote. He didn't call it the Freeze Ray for nothing-but although he thinks he fixed the feedback problem, he only has about two minutes for certain, and he needs to work fast.
It's easy, better than any rush of inspiration he's had in the lab; it's like a clear filter has been laid over the world, bringing everything into crystal focus. He's heard of adrenaline rushes giving people absurd bursts of strength; he supposes this is what he gets instead, and even though he's barely containing shuddering panic, he finds himself beginning to grin as he darts around the room, snatching anything that looks like it might be useful off of the ground.
"Seems I win, in the end, I can be what Hammer's not
Guess when push comes to shove I am better than I thought
Mr Cool, Mr Right, Mr Know-it-all is through-
Then again, in the end, guess he helped me to save you
Who showed me the light..."
The shards of the Death Ray are still on the ground; it's irreparable, but there are enough salvageable components left for what he needs, and he can piece together anything else from the abandoned cell phones and cameras scattered everywhere. The power source is a quartet of AAs stolen from the soundboard, the 'barrel' is a broken chair leg, and the entire thing is held together with a roll of duct tape that had been left under the podium; it won't be very reliable, but he only needs it to work once.
There's no time to test it, so the instant it's finished, he sprints to the Freeze Ray, which hasn't powered down yet. He almost doesn't want to turn it off-at this point, it's the only thing keeping her alive-but his on-the-fly invention won't work if she's temporally frozen. His timing will have to be really, really good.
"It's a brand new me, and I've got no remorse
Though the water's rising, I can run this course-
Gonna shock the world, gonna show Bad Horse!
It's a brand new day-"
He takes a deep breath to steady his nerves, and flicks the switch.
The freeze ray powers down, Penny shudders back into motion, and he dashes to her side, activating the kluged-together (and poorly-named) Heal Ray as soon as he's within what he thinks is range. It's a moment before he thinks to pull out the shrapnel before she heals around it, apologizing the whole time even if she is unconscious. The gun works slowly; all it does is speed natural processes, and it's not terribly powerful, but it works; it's fixing her, and he feels like his heart might burst with pride-finally, finally, finally, just when he needs it most, finally he's made something that works. There's not much to do beyond hold the beam steady, but he sings under his breath as the ray does its job.
"So now I can see the real me,
Not a joke, not a dork, not a failure-
And I think I see what Penny sees:
I've got hope, 'cause I know I can save her..."
The largest of the gashes closes over, and he can see the blood flow slowing, now stopping, and his voice gains a triumphant strength; he can't stop grinning like a fool and he doesn't care.
"It's a brand new day, yeah the sun is high
All the angels sing, 'cause I won't let you die!"
The journalists who have remained, and a few who have crept back in, are lined around the edges of the room; they were watching silently, but now they're beginning to point and whisper. Of course they're confused; he's a villain helping an innocent, from their point of view, but they're distracting him and for some reason he finds their incredulity infuriating. He twists around to glare at them venomously, his grip on the ray gun never wavering as the last of Penny's injuries repair themselves. "Go ahead and laugh-yeah, I'm a funny guy," he snarls in rhythm with the tune in his head; the reporters shrink back and fall silent even though with the Death Ray destroyed he can't possibly hurt them. When he's satisfied they won't bother him, he turns back to Penny, expression softening. He feels the rush of hope flickering, feels the despair creeping in around the edges, but he won't give up, can't give up, not yet, not now.
"Please open up your eyes..." he sings pleadingly, searching her face for any flicker of motion, any hint that Penny is still alive, not just breathing. She doesn't move, and as the moments tick by the beat in his head fades along with the brilliant, adrenaline-fueled clarity, until he's just Billy, kneeling on the floor next to the body of someone he couldn't save.
"Penny?" he asks softly; his voice cracks, but he doesn't care. He can't have failed. Not now, not when he was so close... He takes her hand and it's warm, but it's unbearably empty. The shrapnel's gone, her injuries are healed, she's breathing, but there's nothing there.
"No…" he murmurs, won't think 'whimper', and then with increasing volume and vehemence, "No, no, no, no, no! No! No, goddammit, no!" He punches the floor viciously with a suppressed scream of frustration. "It's not fair!" He hasn't said those words since he was twelve, and he knows how ludicrous they are, but it really isn't. Not when it was going so well, not when he thought he finally had a chance at—maybe not happiness, but something, and it feels strangely vindicating to voice the feeling he's been harboring so long. "It's not fair, it's not fair, it's not fair it's not fair it's not fair…"
Before he knows what he's doing he's sobbing helplessly, repeating her name over and over as if it could somehow call her back. Something in him twinges, a ghost of inhibition-he is Doctor Horrible, a villain, and villains do not cry. Fuck that, he thinks; he's Billy despite the lab coat and goggles, and Penny is gone, and he couldn't stop crying if he tried. He can hear cameras flashing somewhere in the background, but he can't even summon the willpower to glare.
Someone touches his shoulder, and he snaps his head up, ready to lash out at whoever has approached him-and freezes, as still as if his own invention has been turned against him. "Billy?" she says quietly. "Are you okay?"
He can't move, can't even think, can't do anything but stare until she leans forward and pulls him into a hug, and then he breaks up completely-he's crying again, but laughing too, she's alive she's alive she's alive I did it I did it I did it-
"I thought you were d-" he chokes, can't say the word, but she understands him anyway.
"Ssh," she murmurs. "It's okay. I'm okay now."
He pulls his head up, staring at her. "Y-you saw? But-how-?"
She shakes her head. "I guess your... time-stop beam doesn't work as perfectly as you thought it did."
It's something to look into; he's not sure how it's possible, but it doesn't matter right now because it did what it needed to. Another thought occurs to him. "Wait-you don't-" He gestures wordlessly to the coat. "I mean-"
"You could have killed him," she says, and as she looks him in the face her smile becomes even brighter; it's like staring at the sun, and his heart is pounding like a piston. "You could have, but you didn't."
"And anyone," she finishes over him, "who can turn a weapon into something to heal can't be much of a villain at all."
A sheepish grin begins to creep up the side of his face, and this time he's the one who reaches for the hug. "I guess you're right," he says into her shoulder, then-and even now, he can't stop stammering, and his voice barely breaks a whisper-"I l-l-love y-you."
He feels a brief rush of panic; now he's gone and ruined everything, and it had been going so well. He rushes to repair the damage. "I-uh-I l-love-"
"Oh, Billy," she says, and she turns her head to brush her lips against his cheek; his heart stutters, and he waits, hardly breathing, for the end of the sentence.
After an excruciating moment, she sighs. "I can't. Not now. Not after... I won't do that to you."
"O-okay." He grins weakly. She hasn't turned him down outright. She doesn't mind the coat. And she's alive, alive and in front of him, and as far as he's concerned life hasn't just thrown him a bone, it's handed him an entire steak with garnish. "Okay. I... That's okay. That's great. We're... we're still friends, right?"
She nods. "Of course, Billy. Of course."
They stand together, turning in unison to face the phalanx of advancing journalists, and when, with a spike of nervous bravery, Billy takes her hand, she laces her fingers through his, and he thinks he might just melt with happiness.
It's a brand new day.