Very nice. I’ve seen the Charles River on the 4th of July, so that resonates. The pace and tone are good. Nitpicks:
You used the word “they’d” in the 3rd sentence in the 3rd paragraph. That confused me a little, and had me looking for the referent, which I came to assume was Sal and Sue. There’s a sentence fragment in the second paragraph which could easily be tacked onto the preceding sentence.

Interesting – not the setting I had imagined…
Operatives, betrayal, missions… are they spies or something?
The laser fire gives it a sci-fi feel, whereas “The Summons” had me thinking supernatural and horror.
The fact that Mat is laying down in a corner (sleeping?) and being allowed to do so makes it seems almost like there’s a lack of concern regarding the apparent fact that they almost got hit – and the enemy’s aim is improving. Unless perhaps Mat is wounded or something?

August,

Thank you for reading and commenting. I’m glad the Charles R. resonates with you. The last time I went (years ago) the fireworks all went off together and people had to jump ship. Quite a display. Thankfully, no one was hurt. Your assumption is right. I’ll check out the sentence fragment. Thanks again. ;o)

Rose,

That’s probably because at first I wasn’t sure what was going to happen. Yes, spies in the future. I’m not sure if there will be any supernatural components, as for horror, probably not. I’m not a horror fan, though there may be some suspense. Mat isn’t sleeping. He’s gravely wounded. I’d hoped these sentences would convey that. "Mat hadn’t said anything for hours. If they didn’t get out soon, he never would. " I’ll have to take a look. I appreciate your comments. They make me think. Thanks for reading. :o)

Very tense situation, has that dark, grim feel to it all. I wound up a bit confused, but it is early, and I’m on cold medicine. Feels like you’re going for a style thing, which mostly works, though the sentence that starts, “His sister…” is a fragment and feels out of place.

THX,

I’m not surprised that you were a bit confused. I’m getting mixed signals from my characters who can’t seem to decide which kind of story they’re taking part in, LOL. It’s funny that you should point out the “His sister…” line. I had the hardest time placing it. I may play around with this prequel and/or others to see if I can come up with something better. Thank you for reading and taking the time to comment on this for me. I hope you feel better soon.