The marathon spectator had turned the corner off Boylston Street on to Dartmouth Street when the blast hit an estimated 75 yards away.
"We felt the percussion and felt the air move and there was a lot of noise," the Manchester resident recalled Saturday. The crowd was running away, thwarting his attempts to run toward the blast site.
While walking his dog Saturday, Want saw a string of letters on signs spelling out "B-O-S-T-O-N S-T-R-O-N-G" at Derryfield Park, where a fundraiser was going on to benefit the bombing victims.
Want, who turned over his marathon photos to Homeland Security officials, made a contribution to the cause and pondered the effect of the twin bombings on the race's future.
"It will take something away from the race," said Want, who said he has completed the Boston Marathon twice. "It will never be the same, especially at the finish."
Vanessa Underwood of Plaistow and a sister, Grace Freije, a former city school board member, organized Saturday's fundraiser.
"We wanted to do an event while it was still high (in people's minds)," said Freije, an art teacher at Bow High School.
Underwood is hosting a similar event at 3 p.m. today at 92 Newton Road in Plaistow.
"It's about coming together ... and showing our strength," said Underwood, who has volunteered at a few Boston Marathons and plans to run it next year.
"I'll crawl if I have to," said Underwood, owner of Underwood's Sports & Fitness in Plaistow.
A third sister, Patricia Lord, hopes to host a similar fundraiser in her town of Bow in a few weeks.
Saturday's participants went through a voluntary "boot camp" of squats, stretches and kicks, drawing even Mayor Ted Gatsas.
Manchester residents Jaime and Matt Devine brought their two young children, Ryan and Emma, from the nearby playground to participate and make a donation.
"It's an easy way to show that you care," Matt Devine said.
His wife said the bombing "hits very close to home even though we're in New Hampshire. ... Anything we can do to help."
Proceeds will go to onefundboston.org. The amount raised Saturday wasn't available.