May a man treat a woman or a woman treat a man? Sahih al-Bukhari 5679

Arabic hadith text
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا بِشْرُ بْنُ الْمُفَضَّلِ، عَنْ خَالِدِ بْنِ ذَكْوَانَ، عَنْ رُبَيِّعَ بِنْتِ مُعَوِّذٍ ابْنِ عَفْرَاءَ، قَالَتْ كُنَّا نَغْزُو مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلمنَسْقِي الْقَوْمَ، وَنَخْدُمُهُمْ، وَنَرُدُّ الْقَتْلَى وَالْجَرْحَى إِلَى الْمَدِينَةِ‏.‏
Translation
Narrated Rubai bint Mu`adh bin Afra

We used to go for Military expeditions along with Allah's Messenger (ﷺ) and provide the people with water, serve them and bring the dead and the wounded back to Medina.