Dunno about you but I feel vulnerable as fuck on the tube. Weird atmosphere on Monday (obviously). I've had to walk past the bridge about 10 times already...
The tube is probably one of the safest places to be in London really. They leave every ten seconds or so when you spread it across all the lines. The chances of anything happening on your train, never mind in a near carriage is incredibly slim.
You're far more likely to die in a car on the road or cycling about.
I get it though, that few seconds when you consider it. Just gotta get on with your life.