THE FLOTUS DID cross her husband by entering the limousine. By entering she placed the president is a situation he HAD to act to save her and consequently the Russian President/wife.
I believe the FLOTUS character gambled that her presence in the motorcade would prevent the possible scenario. In that the president would certainly order the motorcade stopped/turned around in order to save his wife. The scenes showed her extremely distressed...possibly wondering when her husband would order the motorcade stopped. Also the FLOTUS character would extremely stressed with the knowledtge that her husband was NOT going to do anything to prevent the attack, thus allowing her in extreme harm's way.
I think it will cause Logan big problems that the first lady survived. He's GOT to go.
My point was she simply hoped that her husband would turn the motorcade around simply because she got in the car.
But she didn't NEED her husband to do anything. She could have simply told the Russian President that she suddenly felt ill. They would have turned off to a hospital, and saved everybody.
She didn't have the guts to completely go against her husband, so she took a passive/agressive approach and hoped that her husband would react appropriately.
When he didn't, she was willing to sit quietly in the limosine and let her guests be murdered. Sure she was going to be murdered as well -- which led me to my conclusion that she felt that so long as she died with them, she had done everything she could do, but she was NOT going to open her mouth and warn them.
NOW, as it turns out it was fortunate she kept quiet. If she HAD told them, then when they were rescued anyway we would have probably had a world war on our hands (what else would you get when your president orders the assassination of a foreign country's president on your soil?
Which is why I couldn't believe this particular plot point. Even if the President was stupid enough not to realise that the terrorists would reveal how they got the information on the motorcade, the other guy MUST have known that, and should have told the president that if he went along with the terrorists, russia would end up at war with the United States, which would kill MILLIONS of americans and it would be his fault.
At least with the gas he could blame the terrorists. And the american people would understand that he couldn't cooperate with the terrorists.
Of course, if he's a republican president the democrats would blame him for the poison gas attack, without explaining how to avoid it, but that's another story.