504 error when manually editting a search count number in the URL

[usman-cottagelabs]

STEPS TO REPRODUCE

1. Navigate to Search -> Works
2. Amend the URL manually to /work/search?recref_mode=0&num_record=99999
3. Hit Enter

ACTUAL RESULT
It takes time before something happens, and that something is a 504. Additionally, the whole site goes down for around a minute or so when doing this.
See recording.

EXPECTED RESULT
Not entirely sure what we want to do here, there are options. Some validation would be a quick fix.