by TnT!
Don't stay in Tokyo too long. You can leave when taking only one damage.But that only reinforces your concept that taking Tokyo is bad. However, timing is everything. With 6 players if you can enter right before the current holder of Tokyo Bay, then you get an extra turn before you are attacked. Taking Tokyo from a badly injured monster will mean they will try not to go back in, and you can use the position in Tokyo to keep damaging them.
Holding Tokyo should be a key part of your strategy. Figuring out how to use Tokyo is a great part of the game.