SAN JOSE — Patients, staff and visitors at Valley Medical Center got a scare Thursday afternoon after someone saw a man with a gun, spurring a full-scale lockdown and floor-by-floor search of the hospital, authorities said.

To the relief of many at the facility, the potential threat literally walked out of the building not long after being seen, and police are looking for him. Still, in the spirit of due diligence, deputies with the Santa Clara County Sheriff’s Office scoured the hospital to clear it of any threats.

“They were making sure our patients, visitors and staff were totally safe,” VMC spokeswoman Joy Alexiou said.

The gun call was especially resonant at VMC in light of a mass shooting Wednesday at the Inland Regional Center in San Bernardino that left 14 dead and at least 21 wounded. The center is a nonprofit dedicated to serving the developmentally disabled.

“As a public-health organization, it hits close to home,” Alexiou said. “People are more sensitized to events, hence the heightened reaction.”

She added that VMC has long preached an “if you see something, say something” ethos among its staff, noting that “those are the instructions of the times we live in now.”

Sheriff’s Sgt. James Jensen said the events of San Bernardino did not influence, but rather reinforced, the tack that the Sheriff’s Office took Thursday.

“This would be our normal response any time we get a call about a gun at a hospital,” Jensen said, “to ensure the safety of the patients, the hospital workers, and the citizens of Santa Clara County.”

The sighting was reported after 1 p.m. at the medical campus on Bascom Avenue. Initial reports were that someone spotted a man with a holstered gun.

“The gun was never out, or threatening,” Alexiou said.

Authorities from both the Santa Clara County Sheriff’s Office and San Jose police responded to the call, Jensen said, adding that deputies reviewed surveillance video to track the man’s movements and determined he left the hospital grounds around 1:30 p.m.

Jensen said San Jose police have a lead about the man’s identity and will continue the search for him.

Jensen said the surveillance video confirmed that at no point was the man seen holding the gun in his hand. Even after concluding that the man had left the premises, Jensen said deputies searched the hospital “as a precautionary measure,” during which patients and staff were told to stay inside their respective rooms and stations.

By 3 p.m., emergency room traffic and access had resumed. The search was completed around 3:30 p.m.

Contact Robert Salonga at 408-920-5002. Follow him at Twitter.com/robertsalonga.