Incident at Oval tube?

According to a police officer leaving the scene, there was an incident at Oval Tube station this morning. He didn't give me any more details.

At about 8:25, everybody was preparing to leave, but I counted at least 2 fire engines, 2 ambulances, 1 services motorbike, 2 medium size police vans and 2 British Transport Police units (sort of a cross between fire engines and police units).

Apparently, buses weren't stopping at the bus stop for some time, but have since resumed. Obviously, there was quite a considerably traffic build up.

What on earth happened? Does anybody have more details?

Edit: See blog comment. Apparently, one person under a train necessitates 10 emergency vehicles.