Another doctor notices the bewilderment on my face and comes over. “There are people literally dying of hypoxia in the hallways,” he says, “and there’s empty space with oxygen dispensers on the wall and no one using them.” What is he talking about? Isn’t the hospital full? He suggests that I take a walk down the hall and make a right, less than 100 yards away.

I swipe open the unit, which usually serves as a post­operative area, with my ID. I see a room about half the size of the E.R. It’s a Sunday, a slow day usually, but still, there’s only one patient, who’s being tended to by a nursing assistant. A nurse hovers nearby. I track the green oxygen dispensers on the walls, these fountains of life that my patients gravely need. I go upstairs to one of the regular floors. It’s calm and quiet. Unlike in the E.R., where I dodge patients, colleagues and stretchers to get around — forget six feet of separation; we’re not able to maintain six inches — here the hallways are free and unobstructed. It’s just a regular hospital floor, but the space feels glorious, luxurious.

It’s the first day of our pulse-ox to-go program. Until this point, I have been opposed to the idea of sending hypoxic patients home with pulse oximeters, especially after learning from the Italian doctors that their oxygen numbers often drop quickly to life-threatening levels — sometimes before the patients feel it. These guidelines seem too unsafe to me. A colleague begs me to rethink this, telling me they will get better care at home with their family members than here in the E.R., at least in its current state. “And I’m saying this as someone who doesn’t believe in these guidelines,” he adds. After witnessing how many patients are suffering in the E.R., I immediately discharge two to self-monitor. I know I’ll probably soon hear the dreaded words — “You know that patient you sent home the other day? … ” — but I have to do what’s best for them right now, with what I have in front of me. I’m hopeful that the field hospital being built at Columbia University’s soccer facility, to be staffed largely by former military personnel, will open soon with a capacity for nearly 300 patients.

This week, our employee-health services is at last starting to routinely test medical workers who develop symptoms that could be Covid-related. Still, I wish we could regularly get swabbed and checked when we know we have been exposed, even those of us without symptoms, so that we don’t inadvertently pass it on to our patients. Some of us are also eager for antibody testing, seeking a sense of security if we end up having antibodies, though it’s probably too early to say whether or for how long that could actually provide immunity.

In the E.R., I run into two co-workers who have recovered from the virus and are back at work. Our E.R. colleague across town is out of the I.C.U. I look at a photo of her eating and smiling on Facebook. The next day, I see on Twitter that James Pruden, a 70-year-old doctor in New Jersey, is leaving the hospital after spending nearly a month in the I.C.U. He was one of the first doctors hospitalized for coronavirus infection in the United States. I didn’t think he would make it, because of his age and how sick he seemed. In a video clip, Pruden, in a blue dress shirt, is wheeled out on a stretcher and points energetically at the surrounding crowd. I’ve never met him, but I’m immediately tearful. I replay the recording four more times. Then I send the tweet to a colleague who works with him. “Something going our way for a change,” he responds. “If he can do this, we sure can.”

Later that same day, though, I get a text that several more of our E.R. staff members are hospitalized, requiring oxygen. I learn that another died a few days earlier. More co-workers are ill at home with symptoms. At night, I open an email that a doctor in Brooklyn forwarded to me with the names of more health care workers in New York City who have died. I hadn’t even heard of their deaths.

Over the next several days, I notice the tone changing during my shifts. Conversations about dying and death are all around me now, the only kind I hear. Either I am having one or the physician next to me is. We spend our days talking to patients and families about the limits of medicine and what doctors can do; we call people to tell them their loved ones have passed away. Then we make another call. And another.