A Vancouver woman is speaking out after a bus driver allegedly abandoned her to deal with a man in medical distress all by herself.

Robyn, who asked that she only be identified by her first name, was riding a bus through the Downtown Eastside Monday morning when she saw a man suffering from what she feared was an overdose.

"He didn't appear to be moving (or) breathing, and it looked like a pretty serious situation," Robyn said. "I made a split-second decision that this person needed help."

The unconscious man was at a bus stop near East Hastings Street and Jackson Avenue, and Robyn approached the bus driver for help. She says his response troubled her.

"The bus driver, if anything, seemed inconvenienced and frustrated that I had brought it to their attention," Robyn said. "He let out a big sigh and it was clear that it was an inconvenience that he had to stop the bus and potentially address the situation."

The concerned passenger said she also asked the driver to call 911, but he told her to make the call instead. Then, after she stepped off the bus to check on the man's condition, the driver allegedly drove off.

"As soon as I got off the bus, the bus driver pulled away. The bus left," Robyn said.

TransLink told CTV News it received a complaint about how the situation was handled, and has launched an investigation.

Spokesperson Jill Drews said drivers are trained to call TransLink's dispatch centre when they see someone in trouble on or near transit, and that operators will then dispatch for emergency services.

"It is not our policy for bus drivers to ignore someone in medical distress," Drews said.

TransLink is still working to confirm exactly what happened Monday morning, but said disciplinary action will be taken if necessary.

A driver on another bus ultimately did call the dispatch centre, Drews said. It's unclear whether the two drivers communicated with each other.

According to Robyn, before paramedics showed up she was approached by someone who was carrying naloxone, the medication used to reverse the effects of opioid overdoses.

The stranger administered a couple doses of the antidote, and the man regained consciousness.

"By the time I left and the ambulance was there, he was alert, he was breathing, he was standing up and he looked like he was going to be OK," Robyn said.

Robyn, who normally carries naloxone in her purse, said she hopes her experience will prompt others to pay more attention to the deadly overdose crisis gripping B.C. She also plans to brush up on her CPR and first aid skills, just in case she faces a similar situation.

"I think it's all of our responsibility as members of this community to address what's going on and look out for one another – that's what community means," she said.

With files from CTV Vancouver's David Molko