A 22-year-old nursing student who uses a wheelchair and is legally deaf was a witness to the entire conflict on the BART train on Tuesday that ended with the stabbing death of Oliver T. Williams.

The Chronicle got the exclusive story with Ohlone College nursing student Sophia Humphrey, who was on board the Warm Springs-bound train Tuesday afternoon on her way home after errands in San Leandro. She had seen the suspect, Jermaine Brim, shoeless and acting erratically when she used the elevator at San Leandro station and purposely tried to avoid getting on the same train car as him. But then there he was, on her car, trying to pull the sneakers off of a sleeping homeless man.

49-year-old Williams, who went by the name Tyrone Hodges, got up to intervene and tell Brim not to touch the man's shoes. As Williams' friends and family have been telling the local media, he would always be the first to defend someone against a bully. Humphrey says that Brim initially dropped the shoe and headed back toward the car he came from, but then turned around and approached Williams, demanding he give him his shoes.

Humphrey says that a fight broke out between the two men, and everyone fled the train car at Hayward Station, including the man who almost had his shoes stolen. The only people left to witness the grisly stabbing were Humphrey and a man she describes as mentally unstable and homeless. She says she stayed on the train while texting police because she wanted to tell them that Williams had not instigated the fight.

The stabbing occurred on the moving train before it pulled into South Hayward station. Humphrey says she did not see the knife emerge, but investigators have said that the knife belonged to Williams and he pulled it out to defend himself.

The homeless man and other witness, according to Humphrey, pleaded with Brim not to stab Williams, and she cried out for him to stop as well. But Brim then allegedly stabbed Williams in the neck and stabbed him five to ten times more. He then fled the train at South Hayward Station, at which point the train stopped and BART police were being dispatched. It's unclear how long it took paramedics to arrive, but according to Humphrey's description it was around 10 minutes — it took eight minutes for the first BART officers to arrive.

During that time, Humphrey launched herself out of her wheelchair and crawled over to Williams where she used her nursing training to apply pressure and try to stem the blood flow from Williams wounds. She says it took far too long for EMTs too arrive, and had she been applying pressure, she believes he would have died before they got there.

In the end, she tells the Chronicle that the ordeal confirmed her belief that nursing is her calling, and that she can respond with action when need. "I would much rather myself have to live through something traumatic and be there for someone else, than not be there," she says.

Previously: BART Murder Victim Remembered By Family and Friends As Happy, Generous Soul