[Ianto's been actively looking for her since his run in with Spike earlier since Rebecca's the one person he can think of who will genuinly be concerned. He wouldn't be surprised if Spike is avoiding her the way he seems to want to with him by she's the only other real friend he has and she deserves to know.
Granted he didn't expect to find her naked in a hot tub. He does his best to maintain eye contact.]