smartjordan:
The questions are not supposed to catch you out but to make sure you are safe out there.
Most of them are easy and often repeated.
Even if you don't know an answer you won't get offloaded straight away. The Senior should give you a break and then ask you a different question. Offloads due to insufficient SEP/First Aid knowledge don't happen that often and then it's normally new starters (and they know, it's just their nerves!!!) or crew who has something different on their mind (e.g. a sick child at home) and are therefore really not supposed to be in charge of an aircraft.
Everybody has a big of understanding for this kind of stuff and you won't loose your job over it. Obviously if it's a general thing it might. But if you passed the initial training you'll be fine!
Don't worry about the briefings, they are the easiest part about the job :-)