He closed the first set of doors and moved to open the second.

Then the four went through another set of double doors to the research center.

A second set of doors, but these were open, too.

A set of double doors to his right led back into the hospital.

Everything you need is there, then turn left again through another set of doors, and right beyond that.

At the end was a set of high double doors.

"Let us all meet back here again in the morning and we will go see what is beyond that set of doors."

They passed through another set of doors and out into the open air.

We followed the old man to a set of doors that opened to the outside.

Back in the living room, she stood beside another set of doors.