I completed the mission and Killed the boss.

I think it gave me an option to leave after getting the data.

I didn't leave but saved and exited the game.

Restarted game, explored the places I hadn't been on the level.

Now I can no longer exit.

I have gone through the level and back to the boss fight but there doesn't seem to be a way to exit.
Started and restarted the save game.

Can't find anything that allows me to exit.

Anyone have any suggestions?

game version 1.1.3.3




STupid Mistake:
Forgot what trigger the exit prompt.
Was off by a square.

This post can be ignored