I don't think Alex and alexsandra will last, it will be over quickly when the show finishes, if it even lasts that long.
The longer he is in, the odder he seems. I suspect because he is in to enhance his career, he wants to be a tv doctor, and has no desire to be in a relationship. He's just playing a game, having a little fun and going along with it.
I also think alexsandra misread it by going all out sexy to bed. All the other girls went in shorts and t shirt pyjamas. There is a huge difference between a sexy elegant dress on a date and appearing in sexy lingerie on the way to bed.
I think in hindsight it was a mistake for her to do it. The other thing she's doing wrong is he said he likes her in black, so she's wearing nothing but black now. It's too try hard. She clearly likes him and is trying, and the harder she tries, the more put off he is.
As for Laura 2s questions I think they revealed her to be exactly what she said she was, highly competitive. The questions surprised me though and showed some deep insecurity,