excel formula is taking longer to calculate. Require a non-volatile formula to calculate

Hi,

I could really use some help and advice on this file. I have a the below formula copied across the column from cells D4:D2000. Its function is to extract data from SheetA with the following

Scan Out - It will show the name of the person occupying this location in column D.
Scan In - The person has left and has returned back the key. It will show the cell as vacant

The issue is i realized the formula takes a bit of time to calculate.

1. Can i check if the formula if this formula can be converted into a vba and will the calculation be faster since the formulas are not in about 2000 cells copied down.
2. Can this index formula be replaced with another formula that is can do a faster calculation

I've placed a sample of the file and shown a couple of samples.

=IFERROR(IF(INDEX(SheetA!C$2:C$5000,AGGREGATE(14,6,(ROW(B$3:B$5998)-ROW(A$2))/(SheetA!H$2:H$5000=E4),1))="Scan In","Vacant",INDEX(SheetA!E$2:E$5000,AGGREGATE(14,6,(ROW(B$3:B$5998)-ROW(A$2))/(SheetA!H$2:H$5000=E4),1))),"")