Are you sure it was 4? We left the park not long before 5.30 and were in our room getting changed for an early evening meal when the fire alarms went off at 6.03. It wasn't a test and looked quite serious, everyone was evacuated from the hotels and the monorails were stopped to avoid further chaos. It went on for about half an hour while Firemen investigated the problem.
Not enitrely sure what happend exactly but we heard that someone had been smoking in their room which raised the alarms.
I just got back earlier today, watch out for my full report on our 5 day visit which will cover all the goings on of this week