Wendy Rawlings never sits with her back to the door anymore. And she prefers to teach in classrooms with more than one exit. Recently her students spotted through the window a young man dressed in black pacing back and forth outside the building. \”If he makes a move, I’m out of here,\” one said, and they all laughed, in a morbid way, about the prospect of a deranged gunman just steps away.

Ms. Rawlings, an English professor at the University of Alabama at Tuscaloosa, pegs the date of that incident as sometime between the shooting at Delta State University, in mid-September, and the one at Umpqua Community College, on the first of October. She’s keenly aware of the number and types of campus and school shootings — when they happened, who was hurt, and the weapons involved.

\”So, yeah,\” she said on Friday, when two more campus shootings took place, in Texas and Arizona. \”You can’t stop thinking about it for 10 minutes before another one happens.\”

Many faculty members are thinking about such scenarios with increasing anxiety. They may crack a few jokes at a faculty meeting, or roll their eyes at the latest administration missive of how to stay safe in an \”active shooter\” scenario, but in the back of their minds there are questions. What would I do if someone walked into the classroom with a gun? Is that student who got angry about a bad grade potentially dangerous? Is my campus a safe place to work?

On social media, their comments are a mix of worry and anger. \”I hate being afraid of my students, but I am,\” wrote one. \”If I’m the next professor to die because politicians refuse to act on gun control, please politicize my death. Thank you in advance,\” wrote another.

\”None of us went into academia with the idea we\’d qualify for combat pay,\” said Kevin M. Gannon, chairman of the history department at Grand View University, in Iowa. He tweets a lot about gun violence and says he’s noticed more fear and anxiety among his colleagues on campuses across the country.

Ms. Rawlings began modifying some of her behaviors following shootings at the University of Alabama at Huntsville five years ago, in which a biology professor killed three colleagues. She’s been distraught, she said, since a gunman killed 20 elementary-school children and six adults in Newtown, Conn., in 2012.

Living in Alabama, Ms. Rawlings is accustomed to gun culture. If someone gets shot during a bar fight, that’s not so surprising. But when churches, schools, and colleges are the targets, it’s different. \”This is our place of work,\” she said. \”It feels perverse to me that I have to worry about it.\”

Frank J. Donoghue, an English professor at Ohio State University, said the prospect of a campus shooting comes up in seemingly every conversation he has with colleagues, including at a recent promotion-and-tenure meeting. \”The way people deal with it is to make nervous jokes, but it’s a real source of anxiety.\”

It doesn’t help, he said, that the administration sends about two messages each week on what to do in such a scenario. Explicit messages, he said, on fleeing and hiding and fighting back. He knows the messages are intended to give people a sense of control, but he finds the advice often unrealistic or futile.

\”I’m in a classroom with just one exit, and I’m at the front,\” he said. \”If anyone would walk in [with a gun], there’s no way out. It’s on the second floor, so we can’t even jump out the way they did in Columbine.\”

Professors say they don’t necessarily change their approach to their students, but they do think more about what reaction they might get when they hand out bad grades, for example. Virginia Wood, who teaches an introductory course in psychology at Kennesaw State University, in Georgia, said she has one student who seems angry a lot. \”If I were to meet this student, damn skippy, I would meet in a very public place,\” she said. She knows the statistics: You’re more likely to get killed driving to campus than you are to get shot anywhere. \”But it doesn’t stop me from getting worried.\”

Claudia B. Lampman, a psychology professor at the University of Alaska at Anchorage who studies how faculty members respond when they are bullied or threatened by students, said women tend to feel more distressed in such scenarios than men do. But she said they are also more likely to report such behaviors to administrators, which can help them get a handle on a potentially dangerous situation. Ms. Lampman has not studied the effects of the rising number of campus shootings on professors\’ feelings, but she expects that pattern would probably hold up.

Ms. Rawlings turned her fears into activism and wrote a letter to the editor of The Tuscaloosa News, criticizing a country \”that values the right of unfettered access to guns over the safety and well-being of its citizens.\”

In states like Texas, which will allow people to carry guns onto campuses starting next year, the possibility of a weaponized work environment is more unsettling still. \”We know that with a prevalence of guns on campus bad things happen,\” said Ron Milam, an associate professor of history at Texas Tech University who, as Faculty Senate vice president, is helping craft a plan to create gun-free zones on the campus.

Javier Auyero, a sociology professor at the University of Texas at Austin, said that, because he studies violence in Latin America, he feels relatively safe by comparison. \”What I fear is that the university will become a place where it is OK to carry guns on campus,\” said Mr. Auyero, who is a member of UT Gun Free, an advocacy group seeking to repeal the Texas law. \”‘University’ and ‘guns’ do not belong in the same sentence.\”