The JFK AirTrain, even with NO fire, can have odd service: On July 7, 2011, I arrived at T1 (from Jamaica), and just caught the inner loop AT heading to T8, at T8, they announced that that was the last stop--from something I heard on a walkie talkie (which one of the employees had), the were going to switch that train to be used for either Jam. or HB.
If OP had known about the disruption of service, he/she could have taken the E-train to Union Tpke. Sta. (instead of HB), and taken the Q10 bus to T4 and then a Taxi or (gambled on the AT) to T8.
It seems the PA tried fixing the problem, by creating a worse problem--they should have run the buses to all terminals.
[I use the AT fairly often, and there is NO reason to have cars packed to capacity due to reduced service--this just alienates pax. If dfw's Skytrain can run every 3 minutes, why can't the AT? The dfw ST is free, since it loops the (very large) airport terminals. The AT charges each pax $5 to ride to/from HB and Jam.--though is free within the airport.]