"Do they shift at will, or does something set them off?" Stark thought about Bruce. He couldn't help it, in fact, his relationship with the Hulk was part of the reason why he'd been willing to make an attempt to capture the Titans alive. He wanted to make sure, as best as he could that this wasn't a situation like Bruce's. He wanted to make sure that there was no help that they could give these beings.
He really didn't like the descriptions he was getting of the other Titans. The last thing he needed was something that big attacking the city, or somewhere else. They really didn't have the kind of weapons or organisation that was needed to deal with a threat that big. Not with SHIELD down and a military that was generally otherwise engaged with domestic defence, security and other conflicts. Even then, it didn't seem like something they'd be able to combat and defeat. After all, if the alien invasion of New York was any indication, their response would be to nuke it any and civilian territory on which it stood.
So maybe this was something he'd have to undertake, maybe -- now that he was staring down a problem this big, what he was really seeing was the warning sign of what was to come and what they needed to be prepared for. Hell, they had some people from the Pacific Rim universe here. If Titans could show up, why not their mermaid godzillas? It stood to reason, didn't it?