In the RAF Sea King, we have an AVAD system of 2 chimes of bells followed by a lady's voice that warns us of : Fire warning/port or starboard, Check height, undercarriage and master caution (ie non-immediate problem). The fire warning and low height are combined with visual attention getters. The voice is at normal intercom level, so it doesn't interfere with flying the aircraft, but if it is a problem, it can be muted by switching off. This system has certainly saved my skin a couple of times as we operate regularly in bad weather at low level and the height warning is a god send. I'm sure most other SAR crews will say the same.
As for serial tasks, not too sure what you are after. The Sea King has the longest memorised check list in the RAF as this allows us to start the helicopter quickly on a scramble - only the pre-lift checks are challenge and response. Likewise, all our checks when we arrive at the scene of rescue are memorised to save time. On a similar line all our immediate actions following a major mechanical failure are memorised so that the problem can be dealt with before we fall out of the sky!
Hope that was of help