Creating a Real Time Elapsed Time Counter for an excel spreadsheet. Showing total elapsed time wedged in between Time In & TIme Out.

Need to do two things in excel.

1. When I move to a cell the "TIME IN" cell automatically picks up the time stamp for the current date and time. Colum A & B
2. Once that cell (Column B) is filled with a time stamp another cell in a corresponding row/column starts an elapsed time clock that starts counting up.
3. Then when I move to the "TIME OUT" cell the elapsed time stops leaving the total elapsed time in the

Is this possible to do. ..?
Column A            Column B         Column C                                               Column D
Date Start            TIME IN            ELAPSED TIME                                       TIME OUT
12/27//2018        12:54:28           Displays counter in real time.             12:56:58
                                                        Hrs:Min:Sec    00: 02: 28..,29..,30