Any air ambulance carrying the HEMS exemptions are exempt from a number of normal rules and regulations that a ‘normal’ aircraft might require.
They usually pick their landing sites from overhead taking into account the risk to the public and property on the ground before committing to the site. If things change such as a child runs out then ordinarily the approach would be aborted and they’d go somewhere else. It’s a constant dynamic risk assessment.
No Marshallers are ever required and sometimes an enthusiastic member of the public might decide to do their best impression of one but those are usually given a stiff ignoring.
If the helicopter and crew weren’t there long before leaving it’s likely that they weren’t required on that particular job.