This might seem obvious but are we going with the assumption that each player cannot end their turn before the 30-second mark? For example if player1 takes 5 seconds and player2 takes 10 seconds that means only 15 seconds have elapsed and dividing it by turn timer (30) we get 0.5 and that means only 1 turn despite this being turn2
Simply put
→ Starting with player1 (turn 0) 5 seconds
→ Player2(turn1) 10 seconds
→ This should be turn2 (But going by the example this is considered turn1 = 15/30 = 0.5)
Sorry if I overcomplicated this but I need more clarity before I continue