Interrupted at the Peak
最中に marks the height of an activity, and something almost always interrupts it.
- 会議の**最中に**電話が鳴った。(The phone rang right in the middle of the meeting.)
The second clause is nearly always unwelcome. That built-in inconvenience is the pattern's character.
It Needs an Ongoing Activity
The first part must be something actively in progress, so verbs take ている:
| ○ 食べている最中に | in progress |
| × 食べる最中に | not yet started |
A state does not work either: ×寝ている最中に is odd, because sleeping has no peak. Use 間に.
Against 間に and うちに
| Pattern | Sense |
|---|---|
| 間に | during a span — neutral |
| うちに | during a closing window — act now |
| 最中に | at the peak — and interrupted |