First of:
MOOC is *NOT* the way to address this. At all. MOOC is for major transgressions that concern the entire Marine force. Stuff like an improper mutiny or riot where mass punishments are probably gonna be issued. This concerns two, maybe a few more people getting OD'd. Do not use MOOC which is visible to everyone.
Second:
If you are playing and are witnessing someone doing this, then you are considered to be 'biased' and 'involved'. As such, under most circumstances, you CANNOT take an ahelp about the situation and cannot aghost and PM them, because your judgement will inevitably be biased. Another staff member would have to handle it. The only way for you to bwoink them is if they started outright ignoring everyone and ODing people en masse in a blatant attempt to mass grief. Since this would massively derail the round, you should intervene despite being involved for the sake of maintaining enjoyability and playability of the round.
Your first suggestion is very good. ICly handling it by either telling them how to do their job right, or otherwise handling the situation in-character over comms (maybe inform Command/MPs) is good.
Informing staff is also good. If you are the only staff member and witness a rule break, you will be able to ping moderators/admins on the staffcord to request assistance and have them handle it that way. If none respond, then you are stuck resolving it ICly. Maybe ziptie them and bring them back to the ship.
After the round, you should make a player report about the incident for admins to review. You cannot retroactively bwoink them once the round ends either. In this instance, unless it's mass grief, you are effectively the same as any normal player and will have to player report if no active staff take the ahelp you made.
Wrong answer therefore. Staff cannot resolve situations they are personally involved in, as stated in Staff protocols.