I have a colleague that got for the office a Time Crisis with the gun and everything!, this got me super excited as it brought me back so many child memories and now trying to do again my record there, but getting stuck on the helicopter with the bug that can be hit only on a special part of the tail, and is getting very frustrating and also ruining my record times

I want to see if there's anything that can be done to improve that cheat to leave it always enabled, don't know much or why is nasty, or why is better to turn it off if not in use.
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<cheat desc="Hit Helicopters Anywhere"> <comment>Note, this cheat is quick and nasty and may have side effects so turn it off when not in use</comment>
<script state="on">
<action>temp0 =maincpu.md@00C396</action>
</script>
<script state="run">
<action>maincpu.md@00C396=60000594</action>
</script>
<script state="off">
<action>maincpu.md@00C396=temp0 </action>
</script>
</cheat>
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If the nastiness of the cheat is because if modified that space in memory of the rom the whole time, would it be possible to disassemble the ROM, make that change and assemble it again? As we don't have a keyboard and mouse connected to the machine all the time is a bit tricky to pause, enable the cheat, kill the heli, pause, disable the cheat.
Thanks for any help, I'm happy if I'm directed to some docs to read and try to help on fixing this

Mona (that is not a girls name, but monkey)