[muchadoaboutnothing]

I think, when backed into a corner, Jemima fumbles her words and doesn't think of what she is trying to get across. Had she had to opportunity she might have said 'yes my daughter died but she was fine when the paramedics arrived,' but Jackie was too busy trying to gain brownie points for her daughters hard life. It must have been a terrible fright for Jemima and very traumatic to find (or see) her daughter in such danger. Jackie was the one at fault by constantly defending her daughter even to the point of letting the public know private stuff about Charlie. Dan realised that Jemima was not able to explain what she was trying to say and therefore exploited the situation for his own gains just the same as he did when he backed Dexter into a corner and then laughed at Dexters inability to say what he was trying to explain. It was like watching an interrogation - a detective at work.