That's because he didn't:
Source (Archive)
Yeah, didn't think so. There is a crazy amount of disinfo about this case.
The first reports from the police said he (the shooter) was hanging around for about 10 minutes prior to the shooting. Fox news has an interview with some dude that claims the shooter was hanging around the entire night:
https://x.com/FoxNews/status/1864483413266256163
This possibly indicates he didn't have any inside intel or as grand of a strategy as some people think and probably just knew there was a conference and had pictures of some "key people" and went after the first one that he recognized.
I doubt that a contract killer wouldn't be hanging around for hours like that, neither would someone with heavy experience in this kind of thing. Premeditated for sure, and they for sure had an escape strategy planned ahead of time, but I don't think this was a contract killing.
Looking at the video, it's clear that the shooter only got two-three rounds off as his gun wouldn't stop malfunctioning. I don't care that the general New England region has strict prohibitions on guns etc, you still find a way to ensure your weapon is gonna function correctly at least most of the time, especially if you are doing this for someone else. Combined with the fact that they might have been out there the whole night waiting, definitely seems like an independent venture.
Judging by the fact that he didn't have time to test his weapon configuration, I'd wager he had a time constraint for getting this done, even though he was there the entire night. Maybe local friends or family would've noticed his disappearance, he lived out of state and needed to catch a flight back, wouldn't have had a suitable alibi, etc. Either way, he might have had a limited time window, just recently received the suppressor, and wouldn't have been able to do this on another date. TLDR he likely isn't some uncle ted type dude in the woods somewhere with unlimited time.
Lastly, looking at how he handled himself, it's clear to me that this dude is either a former law enforcement, military, or any similar profession. A lot of people underestimate the type of mental ability it takes to walk up to someone and shoot them, be able to clear multiple malfunctions and continue shooting them, and then calmly walk away without looking back, panicking, and navigating the most camera/police-filled city in the USA, and the police losing your trail, he definitely knows the city well, probably practiced the route prior. The average person would be traumatized as hell after just one shot and would've made a mistake somewhere immediately after or during the shooting, and forgotten the entire plan.