Using the lvl 4 spell from "Wind Law" Stun Cloud I as an example (Rolemaster Unified Spell Law pg 159), but this question comes up for other spells.
- Stun Cloud I – Creates a 5'R cloud of charged gas particles.
The cloud takes one round to form, so anyone in the radius when it is cast may make a maneuver to move out of the radius without taking a critical; however, after that anyone within the radius at anytime in the round takes the critical indicated (a maximum of one per round). Following the initial formation round, the cloud delivers a C Electricity critical to all within the area of effect on the first and second rounds, a B critical on the third and fourth rounds, and an A critical on the fifth and sixth rounds, after which it dissipates. It drifts with the wind.
When in the initiative order do people in the cloud take a critical?
When in the next round does it fully form?
Do we roll initiative for the spell, or does it use the caster's initiative?
Does it apply the critical in the Upkeep Phase?
Upkeep Phase: Ongoing effects, such as bleeding, spell durations, etc. are tracked.
pg 158 Rolemaster Unified Core Law Section 8.3 Round Sequence
I think this spell may assume rules that are not there in RMU. In earlier editions persistent spells effects occurred at the end of the round in the "spell resolution" phase.