Puzzle time

[Thrutchy]

This is a difficult puzzle from the latest America vs Eurasia game. Don't answer if you already know.





Here are some important details about the turns:
- turns 3&4: runner trade (each player down a unit)
- turn 5: nothing visible except medic healing into the FoW
- turn 7: first visible action was runner from spawn killing runner at wit. Then the 5hp heavy became visible

As P2, you have 15 wits. What is most likely the best play for turn 8? Why? What's wrong with other possibilities?

Bonus: What could P1 have done differently in turn 7 to add uncertainty such that P2 would have to make a guess at what they needed to do in turn 8.