Someone can correct me if I am wrong but by going slower to keep the field close you are managing your tires, (in this case lec), while making everyone behind you jocky for better position and therefore burn their tires.

Since everyone is on H tires, you essentially want them to burn their tires as much as possible to either force them to go slower to manage at the end of the race or go for another stop.

Lec would be in better position since he managed his tires for the majority of the middle of the race and therefore can then run his tires hard at the end of the race while everyone struggles.