Hospital Visiting Hours

Recently, we went with Z, a friend of ours to visit her sick mother in the hospital. She told us to meet at the big black metal gate at 5:00pm, which we did. However, the uniformed guard stopped us, saying, "It opens at 6:00 pm." He pointed to the sign, which read: 'Visiting Hours: 7:00-8:00 hr, 12:20-2:20 hr, 18:00-20:00 hr.' You have to wait until 18 hr." Resigning ourselves to an hour wait, we backed off and stood in the shade of the wall.

Our friend Z arrived and began talking in earnest to the guard, who was now joined by 2 others. "May allah have mercy on your parents, please let us in!"
The guard, bolstered by his buddies, stood firm and refused, then turned away.
Z spun around and gathered her courage and will. She continued with the other two guards, stating that they had to let us in now because were special visitors from far away.
the first guy returned. Z rushed to him and extended her hand towards his. They shook hands.

The next moment, the guard opened the metal gate. Z passed through and motioned to us to follow her. I walked through and passed by the blue uniformed men. They bowed slightly and said something which I didn't understand.

How did we get through?
Z had slipped the head guard some money.