In my play throughs of the Miskatonic Museum, I have never run into the trouble of running out of time through doom advancement like I have in other scenarios.
The more pressing time factor is usually drawing "Beyond the Veil" and worrying about going through my deck and taking the damage.
I was curious to see what other people's experiences with the scenario has been.
I find that in that scenario the Hunting Horror respawn is the real clock. That thing starts to become really hard to beat after its third or fourth time showing up.