"You're lucky then," he grumbled. Bruce had always said that was the benefit of remaining an urban legend: it was difficult to garner fear as a man in a suit, but an otherworldly spectre of the night would play on their worst nightmares.
Bruce didn't like it when Clark got upset. It sent his protective instinct into overdrive and made him feel the need to... do something. To make things better. "Yes, I hear it," he admitted quietly, scowling to make himself feel better. "You're only one person, Clark. No matter how much power you have, you can't do everything."
He knew his words wouldn't do any good. The demand far outstripped the supply, and knowing what he knew, Clark was too decent to ignore it when he had the means to do something about it. And this plan of SHIELD's offered him an opportunity to do more than he was currently capable of doing on his own.
Nevertheless, he tried one more time. "They're not going to let you tell them where to go. They're going to be the ones telling you where to go. You're a weapon to them - that's all. They will point you and fire, and you'll get to help, but on their terms, not your own."
It was always incredibly humbling to have Clark remind him that he was the last line of defense between Superman and whatever sent him over the edge, making him enough of a threat that death - or something near that - was the only remaining option. Bruce had his own plan: he would of course be the first, the only person to ever take down Superman if it needed doing, for two reasons 1) because Clark would never be able to live with himself if he hurt anyone like that, and 2) because Bruce wouldn't be able to live with himself if anyone but him killed Clark first. But before he did it, he would use every ounce of his not inconsiderable intelligence and skill to save him some other way, so that he wouldn't lose one of the only two friends he had by choice.
Bruce stared at him. He hated Clark's answer. It was manipulative, and unfair, and probably right. Thinking about it, he ran a hand over his face, still not sure he wanted to do it, but weighing not just was Clark was saying, but also what he wasn't. He wanted Bruce close.
Bruce sighed. At least there was some merit in saving the world. "As soon as they cross the line, I'm out," he said."