Earlier two children had gotten involved in a fight, which Mphure broke up.
While order was still being restored after this incident, the intruders were busy cutting a hole in the fence around the school to gain entry.
They marched to Mphure's classroom, ripped off the back of a school desk and beat up one of the children involved in the fight.
This is the school Mphure was placed in to teach for the next two years. Just more than a year later he still believes his decision to stay was the best decision he ever made.
Teach SA is an NGO, established in 2005, that works with the Department of Education to address the national skills shortage in mathematics, science and English. Young graduates with a proven track record of achievement and leadership, but who have no educational qualifications, are carefully selected to join the programme as "ambassadors".
What follows is a month of intensive training and orientation, after which they are placed in typically historically disadvantaged schools to teach, inspire and effect significant and sustainable change.
Teach SA co-founder Richard Masemola intervened at Klipspruit West to remove Mphure from a situation the organisation deemed life threatening, but Mphure insisted on staying.
"Had I left it would have been a matter of working at the same circus, just with a different tent," he said.
Together with the pupils of Klipspruit West Mphure started and registered a Representative Council of Learners, which functions like the SRC.
"In my extra time, I teach at neighbouring schools. In my school alone, I teach about 225 pupils a day in Grades 9, 11 and 12," Mphure said.
He is also responsible for raising one of his matric science classes' pass rate from 8% to 38%.
Emisang Machedi is another young ambassador who teaches mathematics at Mncube High School in Soweto.
As soon as he realised that there were learning and motivation problems at his school, he saw an opportunity to make a difference.
Machedi and nine young professionals on very different career paths joined together to launch the Thought School Initiative, where Grades 8 and 9 pupils have the chance to gain life and educational skills through non-traditional teaching methods.
Since June 2011 they have implemented a programme where the primary focus is to develop the minds of learners holistically.
Teach SA marketing and fundraising manager Ingrid Pearce explained why the initiative is essential.
"Each process highlights key delivery messages: motivation is to instil inspiration and the desire to succeed; cognitive skills train the mind to process and absorb information; education is to instil the principle of learning as a tool and method for success and career education is to inform learners that today's choices will shape tomorrow," Pearce said.