Bengaluru Torpedoes stunned defending champion Kolkata Thunderbolts 15-10, 10-15, 15-13, 15-10 in a nervy Prime Volleyball League semifinal here on Friday. Despite what Torpedoes coach David Lee termed as a ‘timid and slow’ start for his boys, his side managed to get the momentum to swing in their favour early on. While Kolkata kept finding a way to counter the …