It's quite interesting that you keep referring to "A life safety system" , a venue like this will have numerous life safety systems, fire alarm, sprinklers,emergency lighting etc etc etc. All of which will be backed up by secondary power supplies.
From what I have heard from guys on site and reading between the lines of various reports in the public domain, the installation of these are not complete, which itself is crackers, but then it needs to be taken into account the commissioning of these systems, which is not a two minute job.
Tottenhams ground was an example of how quickly a job can go to shit, they were offering mega bucks for lads and got lads from all over the country, problem is its alright having all the "labour" but if most of them are shite at what they do and have no materials or plant to actually do the job then your fucked, which is why Tottenham took so long to get finished, I'm hearing similar for the arena.