Experienced on 961 too.. BC just park the bus, told us to wait,
then alight close the door, then go to Shell gas station to pang
jio.Come back to bus then continue journey. 
Btw dont think holding "it" back is a good idea. Last
time board 176, tho not happened to BC, it happened to a passenger
i suppose, there's poo all over the floor in the trailer section of
a MKI bendy(no wonder the BC didn't notice the poo before he
started out the journey from BP interchange). I dont know what had
happened, but i think there's a commuter who had rectum
problems(maybe an ill person or old people), and just passed it
onto the bus. Yuck! 
