Tony and Bruce had just reached their lab in Avengers tower; a sample of Natasha's blood in Tony's hand, when Bruce's phone rang.
Tony was too busy giving JARVIS instructions to pay attention to the conversation, trying to keep his mind away from thoughts of what would happen if they failed, if they couldn't find a cure.

"Tony... Tony" Bruce's voice was gentle but urgent.
Tony continued busying himself, not sure he wanted to hear what the other man had to say. Tony hated to admit it, but the other five members of the team had become family to him, he couldn't bare the thought of losing one of them. Bruce grabbed his shoulders; forcing him to face him, ensuring her heard what he had to say:

"Tony, Clint is down too. Same thing as Tasha, but less severe. They're sending a blood sample over"
Tony let out a breath he didn't realise he'd been holding. It wasn't good news, but it was definitely better than what he'd been expecting to hear.

And with that both men set to work, silently trying to identify the substance which threatened their friends lives.