Ash- Shaykh Saalih al- Fawzaan, may Allah preserve him, was asked the following question,
If the woman goes on an elevator while three men are inside, is that considered to be khalwah (i.e. seclusion)?
No, as long as there are three men inside. As for a man and a woman alone, then this is khalwah. But as for if it is more than one man, then no, there is no longer khalwah except if these men are under suspicion, (and in that case) it becomes impermissible for her to go up with them if they are people of wrongdoing and under suspicion. She shouldn’t ascend with them, yes.
AbdulFattaah bin Uthman