The race condition in the provided code arises because multiple threads can access and modify the shared dictionaries `self.jobs` and `self.results` simultaneously without synchronization. Specifically:

1.  **Check-Then-Act Race:** In `process_job`, a thread checks if a job exists (`if job_id not in self.jobs`), but another thread could delete or modify it before the first thread proceeds to process it.
2.  **Simultaneous Writes:** Multiple threads could write to `self.results` for the same job ID (if the same job is processed twice) or overwrite each other's data.
3.  **Deletion Race:** If two threads process the same job, the second thread might attempt to `del self.jobs[job_id]` after the first thread has already deleted it, causing a `KeyError`.

To fix this, we need to use a `threading.Lock` to ensure that access to the shared state is atomic.

Here is the complete fixed implementation:

```python
import threading

class JobQueue:
    def __init__(self):
        self.jobs = {}
        self.results = {}
        # Initialize a lock to protect shared state
        self.lock = threading.Lock()

    def add_job(self, job_id, data):
        # Acquire lock to safely modify the jobs dictionary
        with self.lock:
            self.jobs[job_id] = data
        return job_id

    def process_job(self, job_id, processor):
        # Acquire lock to ensure atomic check, process, and delete operations
        with self.lock:
            if job_id not in self.jobs:
                return False

            data = self.jobs[job_id]
            
            # Note: In a high-performance system, you might release the lock 
            # here before calling processor(data) to avoid blocking other threads,
            # but that would require moving the deletion logic earlier to prevent 
            # the job from being picked up by another thread while processing.
            # For this fix, we keep the logic flow identical to the original 
            # while ensuring thread safety.
            result = processor(data)
            
            # Safely write the result
            self.results[job_id] = result
            
            # Safely remove the job
            del self.jobs[job_id]
        
        return True

    def get_result(self, job_id):
        # Acquire lock to safely read from the results dictionary
        with self.lock:
            return self.results.get(job_id)
```

### Key Changes:
1.  **Added `self.lock = threading.Lock()`**: A lock object is created in the constructor.
2.  **Protected `add_job`**: The lock ensures that adding a job is atomic.
3.  **Protected `process_job`**: The entire sequence of checking for the job, processing it, storing the result, and deleting the job is wrapped in `with self.lock:`. This prevents race conditions where one thread might delete a job while another is trying to process it, or where results might be overwritten.
4.  **Protected `get_result`**: Reading from the results dictionary is also protected for consistency.