In 1921 she was in Tel-Aviv when riots broke out among the Arabs, who then attacked Jewish settlements. Along with other Hashomer members, she took part in the defence of the city. At great risk, she would walk around, disguised as a Red Cross nurse, to keep an eye out on developments. Her experience in Russia came in handy as they attempted to smuggle in grenades for the defenders of Petah-Tikva. She hid them among baskets of vegetables and eggs. The car they were in got mired just outside the town. A patrol of Indian cavalry approached. Their role was to search all travellers for arms. With great presence of mind, Manya averted disaster. She ran up to the patrol, begging them to help rescue the car from the mud. While they were pulling it out, she watched the baskets, saying that she didn't want the eggs to break. The cavalry then even provided an escort until they got into town.