Apart from the fact she left slightly earlier than normal, nothing in her behaviour suggested that she did not intend to come back.
Evading the closures Israel had imposed since the beginning of the al-Aqsa Intifada, and tightened for this week's Yom Kippur holiday, the 27-year-old apprentice lawyer slipped into Israel with one mission in mind. Revenge.
Once in Haifa, she identified her target as the bustling seaside Maxim restaurant. Shooting a guard to get inside, Hanadi then detonated a load of explosives.
The blast blew out windows and charred much of the restaurant. Television images from the scene showed light fixtures and electrical wires dangling from the shredded ceiling.
Beneath a fog of smoke, blood and bits of broken crockery dotted the floor alongside the severed head of a woman, presumably Hanadi's. Her black hair was tied in a ponytail.
On the steps outside the security guard lay face down, his shaved head and white T-shirt streaked with blood.
Arabs among dead
Dazed people wandered around in swimming trunks after coming back from the beach, where others remained where they were, enjoying the sunny weather as rescue workers carried away the dead. Senior officials of Haifa's professional football team were among the injured.
Hanadi's mother mourns her - but
family is also being congratulated
It is not known whether Hanadi would have acted differently had she been aware Maxim was frequented by Arabs as well as Jews. Whatever the case, at least four Arabs were among the 18 dead, according to Israeli police.
Arabs, who make up 12% of Haifa's population, became citizens of Israel when the Jewish state was created in 1948 in parts of what had been British-mandate Palestine.
Islamic Jihad's military wing, Saraya al-Quds, said later Hanadi had carried out the attack in retaliation for the deaths of several of its leaders in Israeli attacks.
But family members said the motive was closer to home.
"The only thing that would push her to do that would be to avenge my brother's death," her brother Thahir, aged 15, told AP.
On 12 June, Israeli troops who had come to arrest her cousin Salah, a member of Islamic Jihad, killed him and her brother Fadi. She heard the shots and ran outside to help, but the soldiers forced her away.
Hanadi had always been religious, fasting twice a week. After the killings, she fasted during daylight hours every day. She began reading the Quran as well.
Hanadi finished her legal studies in Jordan five years ago and was supposed to finish her apprenticeship the following week before qualifying as a lawyer, said her family. They were shocked to hear she was responsible for the bombing.
"But we are receiving congratulations from people," Thahir said.
"Why should we cry? It's like her wedding today, the happiest day for her," he said.