What, NOBODY but me used the Silver Submachine gun? I used it in each Silver Shroud quest because it's trademark, eh?

What about the second guy on the platform? He shoots Kent just as fast as Shinjin... I tried using using vats to get both guys, but of course my first shot was the only one that hit anybody, and it didn't kill anyone. The others hit the iron railing.

Eh, and I have no idea how to use criticals... I see the bar show up all the time, but if I hit space it just goes away and nothing happens.

Weird, I didn't have that problem. But I have an obscene amount of shots in VATS with my pistol and it's pretty over powered so I think I managed to do enough damage before they could kill Kent. It's worth keeping him alive cause my silver shroud suit is pretty powerful now after a few upgrades.

To use a Critical, you need to queue up a VATS sequence, then press E to execute it. While that sequence is being played out, press Space to actually execute the crit.