In the fourth round of the Bologna attack, there were several attacking methods used by the attackers. The first method was to use a car bomb, which was planted in a crowded area near the entrance to the hospital. This attack was successful and caused significant damage to the hospital.
The second method was to use a suicide bomber, who detonated himself at the entrance of the hospital. This attack was also successful, causing significant damage to the hospital.
The third method was to use a drone attack, where a drone was flown over the hospital and dropped a device that caused damage to the hospital.
The fourth method was to use a rocket attack, where a rocket was launched from a drone and landed near the hospital, causing significant damage to the hospital.
Overall, these attacks were very effective and caused significant damage to the hospital. It is important for hospitals to take measures to prevent such attacks in the future.