Time Punch Contact Tracing

Perhaps the following will help:
1. Combine start date and time (column F) using: =IF(E2="","",SUM(C2:D2))
2. Combine end date and time (column G) using: =IF(E2="","",IF(INT(E2)=0,SUM(C2,E2),E2))
Note that similar formulas are used in columns M:N
3. Populate a 'filter column' (column H) using: =SUMPRODUCT(((M$1:M$6<=F2)*(N$1:N$6>=F2))+((M$1:M$6<=G2)*(N$1:N$6>=G2)))
To see the employees that have start or end date/times that overlap the compromised date/times deselect the zeros and blanks in the filter of cell H1.
Note that I removed the merged cells and filled in the blanks in column A so that the employee name would be visible when the filter is applied.
Let us know if you have any questions.