Is passing between fast-moving cars instead of using the pedestrian overpass designated for it considered throwing oneself into destruction and a sin? Is this permissible for the elderly or for those who fear missing the opening Takbir (Takbirat al-Ihram)? And if death results from this, is it considered suicide?

It is not permissible for a Muslim to expose himself or others to danger. Crossing a highway instead of using a pedestrian overpass is dangerous for both life and property. Preserving life and property are among the fundamental universal principles in Islam. As for the elderly and those for whom climbing stairs is difficult, they should go to another mosque or take another route. If this is not feasible, they are excused from attending congregational prayer. If passing over the bridge involves hardship, then congregational prayer is waived due to hardship and difficulty, while emphasizing the virtue of attending congregational prayer and its obligation for those who are not excused.