Definition of "on a mission"

So she walked and as the night begun[sic] to engulf the countryside Emily still did not tire, she was on a mission; a mission to save her friend, her sister.

2014 March 5, Keira Donegan, “We’re Not Alone”, in The Truth and Other Lies, [Bloomington, Ind.]: Xlibris, page 39

Gareth Southgate's side were on a mission to travel one step further than any England side has done since the 1966 World Cup final win against West Germany and they finally achieved the long-cherished goal as they came from behind to beat Denmark after extra time.

2021 July 7, Phil McNulty, “European Championship – Semi-final: England 2 – 1 Denmark”, in BBC Sport‎, archived from the original on 2023-04-12

I'm slipping on my khaki suit (Which one?) / The blue one, gun by my side as I mob to the beach / On a mission and I'm fishing for my DJ Warren G

1993 November 23, Calvin Broadus Jr., Andre Young, Delmar Arnaud (lyrics and music), “Gz Up, Hoes Down” (track 18), in Doggystyle, performed by Snoop Doggy Dogg, Los Angeles, Calif.: Death Row Records

Unfortunately for that relationship, I was a train wreck from day one. All I could think was, Where can I get some drugs? I was on a mission, as I called it. I knew that if I could find Jeremy, I would be able to get high. I had heard he had advanced to harder drugs. Plus, I trusted him. Either way, I had to find something.

2015, Tracey Helton Mitchell, “Let’s Get This Out of the Way”, in The Big Fix: Hope after Heroin, Berkeley, Calif.: Seal Press, Perseus Books Group, pages 42–43

I was with a patient, Loretta. “That guy is on a mission,” she told me. ¶ “What does that mean?” I asked. ¶ “A mission. You know, a mission. He needs some crack. He’s on a mission.” […] “I know. That guy is on a mission. I recognize it. Any crackhead would. I seen it many times.” Loretta had been there. She’d first come to me after spending a year in a halfway house getting off drugs.

2015, Susan C. Ball, “1999: Coping with a Different Paradigm”, in Suzanne Gordon, Siobhan Nelson, editors, Voices in the Band: A Doctor, Her Patients, and How the Outlook on AIDS Care Changed from Doomed to Hopeful (The Culture and Politics of Health Care Work), Ithaca, N.Y.; London: ILR Press, Cornell University Press, pages 225–226