If it had been a slammer you would have been able to see out of the droplight.
I was on a '377, but this was 2005, and I easily could have been on a slammer. If the driver had already left, then, on a '377 I'd have been locked inside the train, but if it had been a slammer, then I probably would have been able to climb out of one of the droplights in the Guard's/Luggage area, or directly behind the cabs where there were no bars over the windows and gained assistance (after taking pictures, of course).
Of course, a door could have been left unlocked or I might have had something I could have used as a carriage key, who knows?
Anyway, we walked back to a small staff halt/platform leaving the '377 in the sidings (leaving probably one of the best '377 picture opportunities I've ever had as I had to climb out of the cab, etc).
The view was absolutely fantastic on this small metal halt because it was at the junction just before Batersea Park station (Factory Junction is it?), and I'd have taken pictures, except for the fact that the driver was pissed off at me (I think he thought I was up to no good) and if he knew I was an enthusiast he might have thought I'd done it deliberately (which clearly I hadn't).
That is one of my major regrets that I didn't get pictures, as it would have been a totally different location altogether, and after that I did vaguely consider doing it again deliberately, but I decided I'd better not! (Especially if I ran into the same driver or it was one of the few who knew me and would have known fine well what I was doing).
A slammer heading into Victoria (a VEP with a 39xx number) doddered up and stopped at the signal beside our platform and I entered the train, startling a lot of passengers inside as I'd seemingly entered whilst standing on thin air!!
Any drivers from Southern will probably know where I'm talking about.
A bunch of sewerage farm workers from the North West were visiting Blackpool on a day trip when one of them was overcome by the fresh air and fainted.
It took 7 buckets of S**t just to bring them round again!