Is it permissible for my wife to train in a medical laboratory inside an apartment alone with a strange man, knowing that the apartment door is open?

The definition of prohibited khalwa (private seclusion) has been previously explained as the seclusion of a man and a non-mahram woman in a place where the entry of a third person is not assured. In this situation, the limited movement of people in the place makes it a cause for suspicion and a reason for fitna (strife/temptation). Therefore, it is not advisable to allow your wife to train there, as "blocking the means to the forbidden is obligatory." And whoever abandons something for the sake of Allah, Allah will compensate him with something better, for Allah Almighty says: "And whoever fears Allah – He will make for him a way out" (Quran 65:2), and the Prophet, peace and blessings be upon him, said: "Indeed, you will not abandon anything for the sake of Allah, the Mighty and Majestic, except that Allah will replace it with something better for you."