2 Newbie Questions, Spellcasting & dice rolling Options

[Hellish]

I've been reading here and in the shadowrun core rulebook (v3) for about three days now, and i'm very impressed with the game system. But I have some (probably stupid) questions.

1.
This one came up when I was GM'ing an improvised campaign yesterday. The party had a mage (street mage copied directly from the book). The 2 non-mage party members triggered the alarm and the mage decided she wanted to take out the 3 guards patrolling the apartment hallway. She is a hermetic mage, so does that mean she has to draw out a casting circle to cast mana bolt? This looks like it would make her a lot less powerful than the 2 gunslingers.

2.
I've seen examples in the book and here (idiot's guide to the Matrix thread) where characters roll more than 6. How is this possible on a six-sider? Example follows: