slime and pigmen in the end

when you go through the end portal slimes and pigmen are on the platform, i died instantly because of the amount of slimes, i kept going through the portal until the slimes jumped off and i was able to kill the rest, now there's just the pigmen roaming around. What i have found tho is that there seems to be a build up in numbers of slime and pigmen the longer you leave it before entering the end again,,,, somehow.