Assuming we're speaking 120 words per minute, counting in American english, going from 1,000,000 to zero.
Were are speaking 900 k units (1 word) , 1000 k tens (1 word) hundreds (2 words) thousands (2 words), tens of thousand (1 words), hundreds of thousands (2 words). (900 + 1000 * (1 + 2 + 2 + 1 + 2))*1000 = 8,900,000 words
We would need more than 74 k minutes (51 days) if we were to only talk.
I would hardly be possible to speak that long, thus needing 10 hours of cumulative rest for our body and minds.
An optimistic prediction is that we'll be trapped for a minimum of 100 days in that school.
Exhaustion (100 wpm) and British english (units is two words) would add another month to our agony.