What do you do?
Usually the death of a character offers the player the opportunity to make a new character, many times of different classes/archetypes/whatever you want to use to define characters. Shadowrun, unlike other PnP games I have played, seems to be a game that can be very reliant on various roles being filled depending on the style that you're playing.
Let's say, for example, that you are a combat mage and are the only one providing magic support to the team. Due to unfortunate circumstances, you received a double tap to the head and now your eyes are a liquid mess on the ground after two bullets ripped through your skull. It has been very crucial to have that magic support and continuing it is highly desirable, and the only other magic in the team is the physical adept street samurai.
So the pressure is on you to make another mage, not only from the players because of the support you provide, but also from the GM because the style of campaign was written with the belief that the team would have some sort of mage. You on the other hand -really- want to play a rigger, even though the team already has a hacker.
What do you do when the critical roles your dead character filled can't be filled by the character you now want to play?