Marinette didn't notice the way Adrien looked at her. When Gabriel entered the room, she looked off to one side as if to give the father and son their privacy.

(She would have stepped out of the room, except Adrien's grip on her hand tightened when he saw his father, and she didn't have it in her to be the one to pull away first when he needed her.)

She didn't want to intrude. The two of them spent so little time together even before the accident - involving herself in what should be their time just felt wrong. But if she'd looked, she would have caught Adrien's look of confusion. If she'd looked, she would have seen the way his gaze wandered to the door.

She saw none of it, and even if she had, there was no way for her to warn Gabriel about the question his son had asked. Not without alerting Adrien to it. If the man had picked up his phone, she could probably have tipped him off somehow and made it sound like a normal part of the conversation, but he hadn't, and now she had no way to bring it up without causing more questions.

...if Adrien asked, she could take her cue as to how to respond from Gabriel. If he didn't, she'd be able to ask him about it once he fell back to sleep.

For now, though, she tried to make herself as small and inconspicuous as possible. This was their moment, not hers.