You're going to have to be a lot more specific about what it is you're trying to accomplish here if you want sensible advice.

We can't even go on the thin information you've provided so far because it doesn't specify the goals. You say you are "…concerned about preventing any traffic…" but does that mean you're concerned that you might be blocking it when you don't want it blocked, or are you concerned that you aren't blocking traffic that you do want blocked?

If the latter, why are you connecting these two networks in the first place? If the goal is to have the MT LAN blocked from the Internet, why not pull the plug?

Why do you speak of a "Mikrotik switch" when it is clearly configured as a router? (It is also a switch, but that's a separate matter, which may or may not be related to all this; that's unclear as yet.)

It is often simplest to draw a diagram of what you've got configured, post a sanitized version of the existing configurations ("/export") and then ask specific questions about your goals and needs. Vague questions like, "Would configuring firewall rules be the solution?" have no answer without that. Yes? No? Maybe? Sometimes? No one can say given what little you've provided so far.