That decision might get back fired today ! I am sure they would have gone through multiple scenarios before coming up with the decision. England at the moment is struggling to contain or apply pressure on Pakistani batters. Pakistan only need 174 runs and they have only lost 3 wickets. In my opinion it is far easy now for Pakistan to win this test match than England.
The only problem with Pakistan team is that they are unpredictable. They are in very strong position to win the game but in next few overs they have the ability to give this test match to England. Giving a target of 344 on such road is not a wise move IMO. Runs are coming here quite easily and it wont be easy to defend a target of 344 here. Lets see what happens in next 2 session.
Everyone knows Pakistan is unpredictable but you can clearly see in this match they need to chase a small target and have the full 5th day to do it. At the moment they only need 86 runs and they have 51 overs in hand. They have lost 5 wickets which can be a little concerning but I think it doesn't matter at this stage. Mind you they are also playing in their homeground and are aware of the conditions.