A/N: Ammended to fix innaccuracies.

The lights had gone out exactly three minutes and twenty-one seconds ago, which Natasha Romanoff knew because she'd been counting since it happened. Not that she minded the dark or anything like that - in fact, the shadows had become a sort of second home to her since she was very young - but the newly-christened Avengers tower looked eerily different without the Arc reactor to keep it going, and it put her on edge. Tony assured them all he was just doing maintenance and swapping out some parts, so she counted the seconds as she searched for someone else in the massive structure. Twenty-five, twenty-six...

'Is anyone there?' came a strained voice. Natasha whipped around to see the elevator. It was closed, but there was a weak light coming from inside.

'I'm here,' said Natasha.

'What happened to the power?' asked Bruce.

'Didn't you hear what Tony said about maintenance?'

'I was in the lab.'

Natasha raised an eyebrow, though he couldn't see it. 'He broadcast a warning on the intercom.'

'I didn't hear it then.' Bruce winced from something unknown and continued, 'I'm stuck in here.'

'You sound like you're hurt.'

'I was carrying some equipment to show Tony. When the elevator jolted, I dropped it and cut my hand pretty badly on a glass bottle. Where are the others?'

'Probably in their rooms,' Natasha admitted. 'I didn't really know what to do with myself, that's why I was out. Should I go get Steve and see if he can-'

'No, please. Don't leave me alone in this metal box. Can you get him to come here?'

Ten seconds later, Natasha had called Steve on her cellphone. Another two minutes and three seconds later, and Steve had wrenched open the doors just enough to allow Bruce to climb up. The elevator had stopped between floors, but Bruce managed to get out after a few tries; and when he did, Natasha finally saw the injury. They said nothing about it as Bruce thanked Steve and ushered him away, but as soon as the soldier was gone, Natasha grabbed Bruce's wrist and stared at his palm. From what little she could make out from the window-light, it was definitely bad.

'I need a couple stitches,' said Bruce as if reading her mind, 'and I can't do it myself. I'm right-handed, unfortunately, and you need both to work.'

'I can't sew you up,' said Natasha. 'I...wouldn't know what to do. You shouldn't have gotten rid of Steve, he could do it better than I can.'

'I trust you, Natasha.' With his good hand, Bruce took her shoulder and smiled gently. 'And besides, I need someone with steady fingers to get this piece of glass out of the wound. You're not squeamish, are you?'

Five minutes had passed by the time they got to the infirmary. The journey had involved a lot of teamwork and choice curses from both, but they were there soon enough, and Natasha was shining a flashlight on Bruce with one hand and picking out a large shard of glass with tweezers in the other. His blood stained the napkins they placed down, and with the punishing darkness trying every second to push in, it was enough to make anyone else nervous. Natasha Romanoff wasn't anyone else. She calmly finished the job and set the flashlight down so it was pointed at the ceiling. She glanced into Bruce's eyes and immediately looked away, getting off her seat.

'I still need stitches,' said Bruce.

'You'll heal.'

'That's why I only need two.'

Natasha bit her lip, something she would never do if he could actually see her. Where she was standing in that moment was just out of the flashlight's reach, just far enough to keep her invisible while she debated. She didn't know whether she could trust herself for much longer around him. As much as she told everyone she wasn't bothered by that day in the helicarrier, the thought of the Hulk still sent shivers down her spine, and she worried that one wrong move with that needle could bring him roaring back.

'Natasha?' Bruce stared blindly at the spot she'd moved to, though he couldn't be sure she was there anymore. 'Are you all right?'

'Of course I'm all right,' she said. 'You're the one with the gaping wound.'

'You make it sound so manly.' He smirked. 'Come on, please? It's just like sewing up an old toy, only with more blood.'

'Your powers of persuasion are too much for me, Doctor Banner. How can a girl resist?' But as Natasha sat down with him again, she was desperately searching for a reason not to. Then she stopped as their eyes met across the flashlight. Out of nowhere, Bruce smiled at her with enough warmth to power the whole building. He gave her the needle and a pair of gloves.

'I trust you,' he said quietly.

Natasha took the needle and put the thread through the eye. As she made a loop, she frowned to herself and said, 'What do you remember about that day on the helicarrier?'

'I remember being scared.' Bruce watched her work, his eyes sad and rueful. 'I remember you, and a promise you made. Everything hurt. I kept thinking about how I was putting everyone in danger and that I never should have come aboard. After that, I only know what I've been told, though I do sometimes get flashes.'

'Like what?' Natasha looked up at him as she put on the gloves, but he avoided her gaze.

'You were terrified. I never thought I'd ever see you like that; not you. I...I raised my hand and then...I don't know what happened next. Did I…?'

'I'm fine, Bruce.'

'Then why did you ask about it?'

'I wanted to know if you were fine too. It's not your fault.'

'But you still keep your distance from me.' He watched her make the first stitch. 'Bit tighter.'

'I'm not keeping-'

'Do I scare you, Natasha?' With his good hand, he stopped her work and met her gaze. He was the one who looked frightened.

Natasha slowly moved his left hand away and continued sewing him up. She hesitated before answering, 'Yes, sometimes. I have bad dreams about that day, and it's not like it's the first thing to keep me up at night, but when I think about you...you as your normal self, I don't know what to feel anymore. I guess...I trust you, too; and that's what scares me the most.'

''Cause you think I'm a bad guy?'

'Because I know you're a good one. I haven't had a lot of those in my life, so it's hard...and with the Avengers I've been...it's just so...'

'Wow, I can't believe I'm seeing you at a loss for words.' But before Natasha could recover and throw him a snippy remark, Bruce added, 'And don't worry, I know what you mean.'

After a moment, Natasha said, 'Well, I'm finished playing nurse.' She showed him the cleaned, closed wound, smiling a small kind of smile. 'I did pretty good, huh?'

'I'll probably need you to take them out in a couple hours,' said Bruce.

'It's a date, then,' joked Natasha.

Bruce stood first, and Natasha's eyebrows crinkled together as she watched him pack up the equipment. She suddenly remembered an incident of pictionary between Bruce, Tony, Clint, and Steve. She'd been watching them from the sidelines, and Bruce had definitely used both of his hands to draw, switching between them like it was nothing.

'Hold on, Banner,' she said accusingly, 'aren't you ambidextrous?'

'You need two hands, Natasha.'

'But you said...'

Bruce pouted dramatically and held up the flashlight so she could see him. 'Does that mean our date is off?'

Natasha was about to respond when suddenly the lights in the room flickered on, blinding them with the harsh white glare that made them blink as they adjusted to it.

'Thank God,' said Natasha. 'I thought we'd have to start up a campfire.'

'You didn't answer my question,' said Bruce, crossing his arms as a smile tugged at his lips.

'You don't get a date with me that easily.' Natasha went over to him and patted his cheek, her eyes glinting with what her mouth wouldn't betray. 'The lights are back on, one miracle at a time.'

'Yeah, how long did were they out for anyway?' The two started walking out together, their arms nearly touching.

Natasha looked away from him and let out a breath. 'No idea. I stopped counting.'