Ahh, you found me... Run!
Placing the last troop triggers the game, but everyone else still gets a turn.
Just to clarify and support what David stated: everyone else does not automatically get an extra turn, you simply continue playing until everyone has had the same number of turns.
I.e. if the player just to the right of the first player (last player so to speak) triggers the end game, no-one gets another turn.