According to their own clocks, which appear to them to tick normally, they cross the event horizon after a finite time without noting any singular behaviour; it is impossible to determine the location of the event horizon from local observations.
They cross the event horizon after a finite time without. This is according to their own clocks. They is noting any singular behaviour. This is according to their own clocks. Their own clocks appear to them. This is to tick normally. It is impossible to determine the location of the event horizon from local observations.