We are with some other agent and we are doing something with him – speaking
or going somewhere – and we are interrupted by other agent or agents –
someone is speaking to us, polymorph approached us or else and we want
to react to these other agents (we are not ignoring him, he is close
enough and etc.).
This event is generated when we have spotted the agent for the first time
or when we haven't seen the agent for some time and we see him again
(emotions are lower in the second case).