It could be done, but not without making enormous changes to the source code.
The only way around it would be to completely change the way that DB parses the DNA.
First, you would have to add a new stack to keep track of requested shots.
Next you would have to remove all shot calls from the regular robot code and shift those calls into DNA parsing.
Next you will need a loop that reads back the shot requests from the shot stack and sends the code to the right routines to make the shots.
The next problem you will have to face is how to integrate secondary shots like -2s, poison and viruses into your new system. These are generated in a different way in response to stimuli which can only be accessed in the main loop of the program and not from DNA parsing.
To be honest, it would be almost as quick to write an entirely new program as it would to make those kind of changes.