Event - I gues you are gonna put this on Map Init. Conditions - None Actions - (Something Here*) Timer - Creata a One-Shot Timer that expires in xx seconds.
*I can't remember exactly whats here right now
Second trigger
Event - "Timer Name" expires Conditions - None Actions - Player - Defeat Player X Player - Defeat Player X
Remember to create a variable for the timer. Varibale= Timer. Right after where you put the trigger ' create a timer...' do Set Variable+(name of timer variable) equal to Last Created timer. Then, put 'Actions- (Variable name of timer) Expires Conditions- Events- Defeat Player XX with (message)