OK let's crunch some numbers.
England are 80 odd ahead after 1 session today.
Session 2 will have a touch lesser intensity due to pacers tiring a bit.
Another 80-100 runs if they score at the loss off 2-3 wickets...then they have 1 more session to have a go at Pakistan where they can get 100-120.
So that leaves them with a lead of 300-320 with Pakistan having to bat a day.
Now this lead isn't enough for a team like Aus but with pakistan you know they won't go chasing it in alien conditions. If they do, they have to risk their lead so that brings in mental demons.
England are playing like its a draw cos they want to get to a position where it can ONLY be a draw or England win and then they will let Paksitan batsmen deal with their own mental demons.
Wickets is the only way to stop them. Unless Pakistan finds a genius plan to contain them to 80 runs per session for all 3 sessions which is unlikely.