Katie,
Carry your HT - folks won't flip - in fact, you'll find them asking you for info! (if you see a big fat guy on the 1 train with a huge green backpack - nod and say hello).

I got lucky in the what, 2003 (or was it 02?) blackout, as my train was in the station

I've been "stuck" in a tunnel a few times, but never had to be evacuated. Most of the time it's been because the train in front of us had a "man under" situation. Thing is, USUALLY they can hold you 1 station back - they open the doors - and you sit for 45-60 minutes or so

The lights in the train DO stay on in a power loss situation - they have BIG batteries, but they go to about 1/4 brightness. The train crew will tend to let you know what is going on, leaving out the gory stuff "Due to a passenger incident in the station ahead, we will be delayed here for the indefinate future" - or if they have more details on how long, they will let you know. This is when whipping out the HT gets you more details for "what to do" (helpfull during the flooding problems a few weeks back) - The MTA Platform director at 42nd st and I were comparing radios - he said mine was easier to understand (I carry a UHF and VHF pair of GE M/RKs or M/PAs)