She says "it was a little bit real watching someone get stretchered off and then blood getting scraped off the track well you're sitting at the top of the 8 metre start hill".
"It was in the back of [my] mind for the rest of the day after that, and to be honest I was like, alright I've made two finals and I'm still in one piece and there's still a lot of Olympic qualifying to go so I'm going to race smart."
She eventually finished last in the final 3.349 seconds behind the Australian winner Saya Sakakibara.
It's no surprise Walker was determined to finish with a clean bill of health, having been involved in a raft of serious crashes herself throughout her career – including a horrific one in 2014, which left her with a concussion and six broken bones in her arm.
With the BMX season ended, Walker will now take up her other role with the International Olympic Committee Athletes' Commission, helping out at the Youth Olympics in Buenos Aires starting on Saturday.
She'll then resume her goal of qualifying for the Olympics when the BMX World Cup season gets underway early next year.
