What is the ruling on missing the Dhuhr prayer due to working in a printing and photography center that is crowded with people and has no place for prayer, along with the difficulty of using the restroom, which causes urinary retention and the sight of spots on the underwear, and what should be done if the employer is a Christian?

Your work involved several Sharia (definition)-related prohibitions: the mixing of men and women, the difficulty of using the restroom which leads to urine retention, and the absence of a prayer area in the workplace, resulting in missing Dhuhr prayer. Mixing and delaying prayer beyond its time are forbidden. Therefore, you must leave this job and repent, knowing that it is obligatory to purify impure spots for prayer.