Wait command in the background without using Parallel Process?

Sounds a bit weird, but here's why:

I run an event that causes an event to move slowly for (say) 8 seconds. By the end, it can move normal again. I can't use a parallel process because this "slow" can happen to different events at different times within that 8 sec time-slot. Thus, one parallel process that controls it all will end the "slow" for all at once as opposed to each individual event per their time-frame.

Here's my set-up (just written in my shorthand. No Call Scripts were used or anything):
->ThisEvent.Change speed = 2
->Call Common Event: Slow
    ->wait 480 frames
    ->ThisEvent.Change speed = 5
End

Basically, I'm trying to make the wait command run in the background like a parallel process for each individual event. I tried finding a script to make a wait command run like it does in parallel. I feel like that would be the best solution without making things too complex. Anyone know a script call for that? A solution where you could (in theory) tag a parallel process per event could be another solution if anyone has any ideas. Again, a script to wait would sound easiest.

Thank you in advance!

You are allowed to use more than one Parallel Process. Just have several. Not sure how many you can have on a map before it starts lagging, but unless you have tonnes of these events then it should work fine.

I was thinking about that, but I just didn't like the idea of having 'n' separate switches and 'n' separate common events to check for. Reason for that is because I'm no good at scripting, so I created a battle system with common events. The idea of (say) 10 switches and 10 common events per status ailment (roughly 5 total) sounded ridiculous. I appreciate the thought however! If there's no better solution, I'll run with it.