In the event that I acquire disease... (2,4)

'in the event' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'i acquire disease' is the wordplay.
I cannot quite see how this works, but
'i' is found in the answer.
'disease' could be 'fever' and 'fever' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...

'that' acts as a link.

Can you help me to learn more?