Which of the following situations would likely require a security guard to use surveillance tools?

Using surveillance tools is particularly valuable in scenarios where there is a high concentration of people and activities occurring simultaneously, as is the case at large events. These environments often involve monitoring for various security concerns, ranging from crowd control to detecting potential disturbances or unauthorized access. Surveillance tools enhance a security guard's capability to oversee wide areas effectively and respond quickly to incidents, ensuring the safety of attendees.

In contrast, monitoring a busy traffic intersection primarily involves traffic control rather than security oversight. A quiet lobby area would generally not require extensive surveillance due to the lower risk of security incidents. Observing public bathrooms is also a sensitive issue that typically does not warrant surveillance due to privacy concerns and legal implications. Thus, patrolling a large event stands out as the situation where surveillance tools are most likely necessary to maintain security and monitor real-time developments.