MissM,
It really is a shame that you don't care. You were hired by BA due to being a caring person, unless you faked it really well at the interview. We are all hired because we are caring people who like working with other people and providing customer service. Basically, you're paid to care, and therefore you should.
In regards to the 777 3-class with 10 crew: At LGW, a crew member comes from Club to WT during 1st breaks. This means the rear galley is covered whilst the other two are doing juice rounds/toilet checks/cabin patrol. It works because we work as a team... If it was a safety/security issue, it would've been changed by now, considering how long we've been operating with these crew levels.
I know you keep repeating yourself in regards to doors 5. It has been pointed out by several posters here as to why it's acceptable to leave doors 5 during demo. If you still have concerns about it, why don't you send an email to CAA? Then you can get the definite answer from the regulators.
Gg