La Sombra isn't 'sneaking' so much as trying to be unobtrusive. The goal is mostly not to be noticed by the guys who have the crowd's attention so she can get close enough to act quickly and with surprise.
The people in the crowd may or may not notice her, she is less concerned about that.
As she moves forward, she readies her gun, but still under her jacket so it isn't 'seen' while also boosting her agility (actually does that first):
Agility Boost: Magic 4 + Agility Boost 4 =
2 HitsRuns out on the second action of the fourth round, at which point she'll take 4 points of stun (ouch) due to soaking
zero of the drain.
For trying to keep the gun hidden under her jacket:
Palming: Agility 5 (+2 for Agility Boost) + 5 Palming =
0 HitsWow, Zero hits out of 19 dice. Orokos is on a roll. Thanks a lot, Orokos! If you count the roll before it, 2 hits out of 27 Dice.
Whatever, she's too intent on her chosen path. At least it wasn't a glitch (though there were 5 ones in that roll).