Samaritan snatches purse from purse snatcher at Copley Plaza

A Redditor recounts an incident at Copley Plaza yesterday:

I was still indoors finishing a text when I herd a ton of shouting so I look up above and see a group of people screaming and pointing towards me! That's when I noticed a young man, possibly mid-20's sprinting towards me and without even thinking I bolted towards him as he ran passed me and yanked the purse out of his hand, he slammed through the revolving door and kept running.