Quiz logic

Hi, I'm looking for some help with the logic of a simple quiz control.
4 separate inputs (momentary pushbuttons) each linked to an output.
When the pushbuttons are pressed, only the fastest can be high.
I've designed following logic but have some questions.
Is there a better way and what with the scan time (first input benefits from scanning time).
I like to hear it

ixo65

In my opinion, your program is not 100% secure.
For example, if I1 was first keyed and immediately released, and e.g. I3 is pressed one cycle later to I1 and also released one cycle later, the two associated outputs (Q1 and Q3) light up.
Because you lock only the keys and not the Outputs.

True, my outputs are not locked.
Don't see a possibility directly.

Tested and approved!