The key answer of exercise 2

a)

1. The crew is / are obliged to seal the exits first ('is' Is more 'correct but 'are' is used equally often).
2. It's everyone's responsibility to have memorised every word they're going to say.
3. Someone will probably be in pain.
4. The flames and smoke must be frightening.
5. There's an expectation that every aspect of service is perfect. / The expectation is that every aspect of service is perfect.
6. The capacity to work in high places without getting vertigo is important.
7. It's imaginable that the staff will know more about the subject than the painters themselves.
8. Most people there will undoubtedly find the motion difficult during a storm.

b)

1. a ship / a ferry / an aeroplane
2. theatre, actors
3. ambulance / hospital, paramedics / doctors / nurses
4. firefighters
5. (five star) hotel or restaurant and employees therein, e.g. waiters
6. builders or window cleaners or painters of high buildings
7. art gallery / museum
8. a cruise ship