Based on prior knowledge, we can infer that there is a relationship between BMI and age. Generally, as people age, their BMI tends to increase. However, there is no specific cutoff value for BMI that determines whether someone is a senior or non-senior. Therefore, in order to create the dictionary, we will classify 'Adult' as individuals under the age of 65 and 'Senior' as individuals aged 65 or above.

Here is the generated dictionary:

```json
{
	"Adult": [18.5, 21.3, 24.7, 27.9, 30.2],
	"Senior": [20.1, 23.8, 25.6, 28.3, 32.7]
}
```

Please note that the BMI values provided are just examples and not an exhaustive list. The values presented here are intended to illustrate typical values for each target class.