Awareness and multi-tasking are not necessarily contradictory. When driving a car, one needs to be aware of many factors at once in order to arrive safely and efficiently. The principal focus is on the road ahead, but one is also frequently checking the speed, weather conditions, mirror, etc. Of course, there is bad multi-tasking such as trying to cook a meal, talk on the telephone, and watch television at the same time.
In Aikido the principal focus is on performing a successful technique. However, in order to do so, there must be consciousness of posture, breathing, movement, and so on. And the power and speed of the technique must always take into account the ability of the partner to receive it without injury. Throughout, it is important to be in the moment. Talking should be minimal and the mind must not wander to ideas or problems outside of the immediate situation of attack and defence.